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Malaysian Journal of Library & Information Science, Vol. 16, no. 3, December 2011: 17-29
Death of web citations: a serious
alarm for authors
Oranus Tajeddini1, Ali Azimi2, Ali Sadatmoosavi3 and Hadi Sharif-Moghaddam4
1Department of Library and Information Studies,
Islamic Azad University, Sciences and Research Branch, Tehran, IRAN
2Tehran University of Medical Sciences, Tehran, IRAN.
3Institute of Biochemistry and Biophysics, University of Tehran, Tehran, IRAN.
4Department of Library and Information Science, Payame Noor University, Tehran, IRAN.
e-mail: tajedini.o@gmail.com
ABSTRACT
The study explores availability and/or decay of URLs cited in articles of six Library and Information
Sciences (LIS) journals published by Emerald, Science Direct and Sage. The research was performed
using a descriptive survey method. Initially, all issues of the six journals including Information
Processing & Management, Library & Information Science Research, Journal of Librarianship and
Information Science, Journal of Information Science, Online Information Review, and Journal of
Documentation from 2005 to 2008 were downloaded directly from their publisher websites.
Afterwards, all the journals' citations in either print or Web formats were calculated manually. Then,
availability and/or decay of individual cited URLs were examined in the Web environments. Two
groups of URLs were identified as accessible (without any accessibility error) or inaccessible (with
accessibility errors). Two groups of accessible URLs were “accessible through first-check” and
“accessible through second check”. Research findings indicated that 66% of articles had web
citations. Original accessibility of web citations was 66% which improved to 95% by second check
availability using the Wayback Machine and the Google. Overall, from 4562 cited URLs 34% had
error messages mostly related to "File error" type. The study recommends that the best solution to
prevent decay or disappearance of Web citations and diminish URLs decay is to check availability of
citations from while they are being published. The Wayback Archive and the Google can revive the
decayed citations.
Keywords: Citation analysis; Web citations; URL accessibility; URL decay; Library and Information
Science journals.
INTRODUCTION
Since the quasi-miraculous emergence of the Web in 1990s, there has been a continuous
increase in the volume of scholarly resources in electronic forms, such as e-books, e-
journals, e-databases, e-theses and dissertations, e-prints of research papers, and the like.
(Maharana, Nayak and Sahu 2006). Consequently, citation behaviour of researchers has
become influential in the continuous process of research. As Zhao and Logan (2002) have
indicated, the Web has become the first choice for seeking information, breaking scientific
discoveries and for keeping up with colleagues at other institutions. In spite of the fact
that the internet has eased the accessibility of information resources and citations, we are
witnessed that the online citations disappear at increasing rates over time (Dimitrova and
Bugeja 2007). Missing online citations are become a controversial issue for researchers and
web managers. According to Rumsey (2002) and Tyler and McNeil (2003) one-third of
online citations vanish from original web locations for several reasons. Hence, the present
study aims to perform a study on the use of web citations and citation behaviour of the
Tajeddini, 0.; Azimi, A.; Sadatmoosavi, A. & Sharif-Moghaddam, H.
Page | 18
authors of articles published in Library and Information Science (LIS) journals. Maharana
and his colleagues declared that citing web resources properly according to an established
style is important in most of the subject fields and it is different from citing traditional
resources.
Apart from the style of web citations, quality, authenticity and sustainability are the issues
with documents on the Web, demanding the immediate concern of the information
professionals (Maharana, Nayak and Sahu 2006). Several studies have dealt with this
general problem of "URL decay". The idea that the internet-based information, unlike the
printed media, can suddenly disappear because of various reasons is often called ‘URL
decay’, or ‘link rot’ (Wren 2008). This study aims to explore availability and persistence of
URLs cited in articles published in LIS journals of Emerald, Science Direct and Sage
publications. In the literature we have a thorough review of studies regarding the issue
URL decay as follows.
LITERATURE REVIEW
After the emergence of the Internet, Web citations have been frequently considered, used
and studied (e.g. in Harter and Kim 1996; Zhang 1998; Koehler 1999, 2002, and 2004;
Germain 2000; Davis and Cohen 2001; McCown et al. 2001; Markwell and Brooks 2002 and
2003; Casserly and Bird 2003; Dellavalle et al. 2003; Spinellis 2003; Sellitto 2004; Wren
2004, 2008; Maharana, Nayak and Sahu 2006; Wren et al. 2006; Zhao and Logan 2002;
Dimitrova and Bugeja 2007a; Falagas, Karveli and Tritsaroli 2007; Goh and Ng 2007;
Wagner et al. 2009; and Wu 2009).
Harter and Kim (1996) performed one of the oldest studies on accessibility and decay of
URLs. From e-journals published during 1993-1995, they examined 47 unique URLs and
reported 31% as unavailable URLs. Casserly and Bird (2003) examined 500 internet
citations randomly chosen from scholarly articles published in LIS journals. They found that
only 56.4% of those URLs were accessible, while the rest were disappeared from the
original web addresses. Furthermore, the study showed that more than half of the online
citations contained incomplete information and the majority did not include a retrieval
date. The study showed that "file not found" was the most frequent error message and
close to half of the online citations were initially unavailable.
Koehler (2004) studied Web page availibility and reported that a static collection of general
Web pages tends to 'stabilize' somewhat after it has 'aged'. The study concluded that the
Web documents are not particularly stable media for the publication of long-term
information and the maintenance of individual objects or items.
Wren et al (2006) carried out an investigation into URL decay in dermatology journals. They
considered URLs in articles published between January 1, 1999, and September 30, 2004,
in the 3 dermatology journals with high impact factor. Of the 1113 URLs, 81.7% were
available (decreasing with time since publication from 89.1% of 2004 URLs to 65.4% of
1999 URLs). They concluded that URLs are increasingly used and lost in dermatology
journals. Loss will continue until better preservation policies are adopted.
Dimitrova and Bugeja (2007a) studied cited URLs in journalism and communication field.
They reported availible URLs as 61%. The .org domain with 70% active links was the most
available domain.
Death of Web Citations
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Falagas, Karveli and Tritsaroli (2007) in a study explored accessibility of online resources of
Lancet and New England Journal of Medicine. They found that 3.9% of the Lancet and 2.5%
of the New England Journal of Medicine references were web resources. The two journals’
inaccessible online resources was totally 62.2% which reduced to 35% after searching
missed URLs into Google,.
Goh and Ng (2007) studied accessibility and decay of URLs of 3 LIS journals during 1997-
2003. They reported decayed URLs as 31%. 56% of unavailable URLs brought 404 errors.
The .edu with 36% active links was the most persistent domain. Accordingly, the half-life of
online resources was 5 years.
In an article by Aronsky et al. (2007), web citations from a 20% random sample of all
publications released in PubMed during a one-month observational study period (Feb 21 to
Mar 21, 2006) were identified. The study included 4,699 publications from 844 different
journals. Among the 141,845 references there were 840 (0.6%) web citations. From the
840 Internet references, 11.9% were already inaccessible within two days after an article’s
release to the public.
Wagner et al. (2009) studied accessibility of online resources of medical healthcare
management journals from 2002 to 2004. They extracted 2011 unique URLs from 5
dominant journals in the field. The accessibility analysis of URLs showed that only 50.7% of
URLs were accessible while the rest were unavailable from their original web addresses.
METHODOLOGY
The objectives of the present study are to:
a) determine the ratio of print and web citations, total and per journal articles, and
total and per journal web citations;
b) specify decay or availability of URLs;
c) determine the URL accessibility/decay of URLs per type of domains and file
formats; and
d) study the resulted error messages at inaccessible URLs.
The study was performed during a six-month period from September 2010 to February
2011. The articles of six LIS journals published by Emerald, Science Direct and Sage
appeared from the beginning of 2005 to the end of 2008 were studied. Selected journals
were as follows:
a) Information Processing & Management (INFORM PROCESS MANAG) (IF= 1.783)
b) Library & Information Science Research (LIBR INFORM SCI RES) (IF= 1.236)
c) Journal of Librarianship and Information Science (J LIBR INF SCI) (IF= 0.581)
d) Journal of Information Science (J INF SCI) (IF= 1.706)
e) Online Information Review (ONLINE INFORM REV) (IF= 1.423)
f) Journal of Documentation (J DOC) (IF= 1.405)
From each publisher two journals based on their JCR impact factor (IF) rankings, 2009)
were selected. Therefore, all 2005-2008 issues of the selected journals were downloaded
to a local disk. Only publications which had citation list were considered for analysis.
Editorials, brief communications, special reports, book reviews, etc were excluded, if they
Tajeddini, 0.; Azimi, A.; Sadatmoosavi, A. & Sharif-Moghaddam, H.
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had no citations. Eventually, a unique set of 40,133 citations were recorded in a spread
sheet. Web or print citations were identified manually.
At the next stage, all web citations were extracted and their URLs hyperlinks were tested
by examining their URLs’ functionality. Initially, accessibility was tested by directly click on
the URLs’ hyperlinks. Afterwards, two groups of URLs were identified as accessible
(without any accessibility error) and inaccessible (with accessibility errors). Two sets of
accessible URLs were “accessible through first-check” and “accessible through second
check”. All URLs which were accessible through the first examination (without error) and
all URLs that retrieved messages indicating redirection (e.g. ‘you are being redirected’, ‘this
page has been moved’, etc.) and returned the right citation content were considered
“accessible URLs through first-check”. Other URLs which were available by adopting
heuristic strategies were included in the “accessible through second check”. Availability
examinations were carried out all weekends and for unavailable URLs which returned 5**
errors (server errors), the availability examination was repeated four times for four
weekends. If then the URL was unavailable, it was recruited for heuristic URL refinement.
We tried to modify unavailable URLs. Therefore, in case we faced with errors of URLs, we
checked to find if the URL content is yet available through the web. Thus, as the first
employed strategy, unavailable URL was entered into the Internet Explorer 7 (IE7) and if
the URL worked, was considered accessible and saved into “accessible through second-
check” records. Otherwise, if it did not respond within 60s or returned an error message it
was considered as “missed URL”. For avoiding unwanted errors, the URL was directly
copied and pasted into the browser.
Missed URLs were rechecked for their likely errors in their strings. Therefore, as said by
Wren (2004) non-standard signs, if any, because of space, %, \\ instead of //, http:/, ++,
http@, non-alphanumeric characters (usually from non-English websites) or other rare
misspelling in the URL were corrected manually, and then the corrected URLs were tested
again for accessibility status. If the nonstandard URL worked into the IE7 browser, the URL
was regarded as accessible and was saved in accessible through second-check records.
Once more, if after a period of 60 seconds yet-inaccessible URL resulted no content or
returned errors (e.g. “404 (not found)”, “page was unavailable”, “file not found” etc,
errors), was regarded as “missed URL”. Otherwise, was recorded in “accessible through
second-check” list. String editing was not saved to the unavailable URLs.
At the next stage, path depth reduction strategy was used for unavailable or missed URLs.
Based on the assumption that the lengthy URLs could be erroneous, a unit by unit depth
reduction was performed. Unavailable URL strings sustained depth reduction in several
steps. URL path depth was specified by a “/” after the top domain. Accordingly, an URL
with just a top domain string (e.g. http://emeraldinsight.com) has a path depth of 0.
Comparably, a string like http://emeraldinsight.com/journals/aslip.html has a path depth
of 2.
Missed URLs were examined through a unique and a unit by unit path reduction operation.
A unique operation was performed for every single of missed URLs. Therefore, after 1 unit
path reduction, the URL was tested for availability. The reduction operation would be
continued until either the path depth was=1 or the broken URL responded. If the URL
worked in any depths ≥1, the operation would be finished and the URL was marked as
available through the second-check. Otherwise (URL with depth=1 and yet unavailable),
the URL was considered as unavailable. Path reduction was not saved to the missed URLs
Death of Web Citations
Page | 21
since they should be recruited for the next URL recovery strategy that was searching
through an Internet Archive.
Thereafter, another availability check was established for the missed URLs using Wayback
Machine1 and then Google search. Wayback Machine is an old Internet Archive (IA) and
likely is the most popular one (Klein 2008). The Google is also the most popular search
engine. Therefore, the missed URLs were entered in the Wayback Machine by copying the
exact URL given in the online citation. If the URL was found in Wayback, the URL was
recorded in the “accessible through second-check records”. If the URL content could not be
found even via the Wayback Machine, it was recruited for Google search strategy stage. Up
to 5 keywords extracted from the citation’s author(s) name(s), title, and resource were
entered to Google and the first 20-retrieved results were reviewed to find the extinct
content.
Finally, if the adopted strategies yielded no results, the inaccessible URL was considered as
“decayed” and the related errors were recorded on specific related notes. Then, the web
citations of the studied journals’ (either accessible or inaccessible) were classified based on
their top domains and file formats. Using Microsoft Excel 2007 the collected data were
analyzed and suitable related tables and figures were drawn.
RESULTS
The Ratio of Print and Web Citations, Total and per Journal Articles, and Total and
per Journal Web Citations
According to Table 1, 1109 inspected articles had 40133 citations, in which 4562 (11%)
were web citations. Average 30.21 citations were calculated for each paper. Moreover,
among all citations (10242), there were 1761 Web citations with the average 5.19 Web
citations" per paper.
Table 1: Distribution of Total and per Journal Articles, Total and per Journal Web Citations
Journal Articles Citations Web Citations
(%)
Articles Citing Web
Citations(%)
Mean of
Citations
per Article
Mean of
Web Citations
per Article
Information
Processing &
Management
406 13407 754 6% 173 43% 33 4
Library & Information
Science Research 109 5029 528 10% 104 95% 20 5
Journal of
Librarianship and
Information Science
72 2268 537 24% 62 86% 26 9
Journal of
Information Science 185 7602 1076 14% 125 68% 41 9
Online Information
Review 176 5362 974 18% 153 87% 30 6
Journal of
Documentation 161 6465 693 11% 116 72% 40 6
Total
1109 40133 4562 11% 733 66% 36 6
1 . Available at: http://www.archive.org/web/web/php
Tajeddini, 0.; Azimi, A.; Sadatmoosavi, A. & Sharif-Moghaddam, H.
Page | 22
Accessibility and Decay of Web Citations
Initially, from 4562 URLs, 66% (3001) were accessible and 34% (1561) were decayed. 72%
of Journal of Information Science URLs’ were originally accessible (best performance), while
53% of Library & Information Science Research web citations were originally active.
Table 2: Availability of URLs at the First Check
Journal
Total number of
URL (%)
Total
Accessible
a
Inaccessible
b
Information Processing & Managem ent 502 (67%) 252 (33%) 754(100%)
Library & Information Science Research 280 (53%) 248 (47%) 528(100%)
Journal of Librarianship and Information Science 310 (58%) 227 (42%) 537(100%)
Journal of Information Science 771 (72%) 305 (28%) 1076(100%)
Online Information Review 647 (66%) 327 (34%) 974 (100%)
Journal of Docum entation 491 (71%) 202 (29%) 693 (100%)
Total 3001 (66%) 1561 (34%) 4562(100%)
a
without any accessibility error
b with accessibility errors
After passing adopted refinement strategies including considering IE7 browse, manual
editing, path depth reduction, searching into Wayback Machine and the Google, the URL
accessibility rate increased from 66% (3001) to 94% (648) and inaccessibility decreased
from 34% (1561) to 6% (45). This means 28% improvement in web citations accessibility.
Table 3 illustrates the improvement results per adopted strategies.
Table 3: Final Accessibility and Decay of URLs
Journal
Total number of
URL (%)
Total
Accessible
Decayed
Information Processing & Management 719 (95%) 35 (5%) 754(100%)
Library & Information Science Research 483 (91%) 45 (9%) 528(100%)
Journal of Librarianship and Information
Science 513 (96%) 24 (4%) 537(100%)
Journal of Information Science 1027 (95%) 49 (5%) 1076(100%)
Online Information Review 940 (97%) 34 (3%) 974(100%)
Journal of Documentation 648 (94%) 45 (6%) 693(100%)
Total 4330 (95%) 232 (5%) 4562(100%)
Death of Web Citations
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Figure 1 demonstrates how accessible URLs were found. Accordingly, of the total number
of accessible URLs, 2699 (64%) were found at cited URL, 495 (11%) were found at Internet
archive, 517 (12%) were accessed using Google search engine, 302 (7%) were found at
another URL other than cited URL, 109 (3%) were found through depth reduction, 42 (1%)
were found by editing URLs and 66 (2%) were accessed through searching missing URLs in
the Internet.
Figure 1: Percentages of Final Accessible URLs
The HTTP protocol defines 24 different errors that can occur within an HTTP exchange.
(Spinellis 2003). In practice, whenever a URL is inaccessible an error message (HTTP code)
appeares. In general, when URLs were checked we were faced with the following errors
that were similar to previous studies (Wu 2009).The error massages have been categorized
into three different types as classified in Table 4.
Table 4: Classification of error massages in case of URLs inaccessibility
Host name/sever Errors
File errors
Access restriction
1. The requested URL could not be
retrieved.
2. Unable to determine IP address
from host name.
3. Name Error: The domain name
does not exist.
4.Here are some related websites
for: qosforum.com
5. HTTP 400 – False request.
6. HTTP 500 – Internal server error.
7. Cannot find the server or DNS
error.
8. 503 Service Unavailable
1. HTTP 404
–
File
not found.
2. Object not found! Error 404.
3. The document you requested does
not exist on this s erver. The document
may have existed previously, but was
removed because it was out of date.
4. The website has been restructured.
We have rearranged our website.
5. Not a very informative URL.
6. Redirect to a new URL and new web
page without consistent content.
7. 410 Gone
1. 403 Forbidden.
2. Windows cannot visit the
folder.
3. Your IP address is invalid for
this session.
4. Your client does not have
permission to access.
5. You do not have permission
to access on this server.
6. Password needed for entry.
401 Unauthorized
Tajeddini, 0.; Azimi, A.; Sadatmoosavi, A. & Sharif-Moghaddam, H.
Page | 24
Figure 2 summarizes three types of inaccessible web citations. “File error” was the biggest
problem, about 56% of cases, “Host name or Sever error” in about 17% of cases and those
needing permission or password (Access restriction) in 27%*.
Figure 2: Percentages of HTTP Codes for the URLs’ Accessibility Errors
Distribution of URLs Accessibility by Type of Domain and File Format
An URL is the address of the location of a digital document on the Web. A URL essentially
has four parts: protocol, domain, directory and file. A domain name is the way to identify
and locate computers connected to the Internet. No two organizations can have the same
domain name. A domain name always contains two or more components separated by
periods, which are called "dots". Some examples of domain names are: ibm.com, nasa.gov,
utexas.edu and tcs.co.in. A domain name can often tell the user if it is a government site,
an academic site or a commercial site. Some common top-level domain name endings are:
• .com or .co: a commercial organization;
• .edu or .ac: an educational organization;
• .gov: an official government site;
• .org: mostly non-profit organizations; and
• .net: traditionally it was for network organizations, but now can be used by anyone.
In this research, five different types of domain have been taken into consideration. They
were .org, .edu/.ac, co/.com, .gov and .net, while those domains not falling into any of
these categories fall into the "other" category.
As shown in Figure 3, the domains of the cited URLs mostly include the .com/.co and .org
types. Accordingly, of 4562 Web citations, the highest number of domains, i.e. 1359 cases
were of .org types and 999 ones were of .com/.co types. This revealed that the data
sources of most of the Web citations in the present study were websites of various
professional institutions or societies and commercial organizations, and the like. Also, 915
domains were of .edu/.ac, 273 domains (.net), 393 citations (.gov) and 623 cases belonged
to domains other than the above types, categorized in the form of "others".
Death of Web Citations
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Figure 3: Accessibility and Decay of URLs Based on Their Top Domains
Similar to previous studies (McCown et al. 2001; Maharana, Nayak and Sahu 2006), the
URLs were categorized into seven different file formats as follows:
• Slash files (/): URLs which end by / sign, for example, http://foo.edu/;
• HTM/HTML/SHTML (hyper text markup language): Web documents created in
HTML scripting language;
• PDF (portable document format): the file format for documents created using
Adobe Acrobat;
• PPT: PowerPoint presentations;
• DOC: documents created using MS-Word;
• RTF (rich text formats): a text file format that includes formatting features, such
as bold, italic, and underlined texts; and
• Others.
The data as illustrated in Figure 4 indicate that the largest number of cited web resources
were HTML/HTM/SHTML files. Of 4562 Web references, 1885 were HTML files, followed
by1126 Slash files, 945 PDF files, 61 DOC files, 11 PPT files and 9 RTF files. 525 files, which
did not match these six categories, were classified as the "other" category.
These findings are in agreement with findings of McCown et al (2001) and Maharana,
Nayak and Sahu (2006) which reported that most of cited Web resources contain
HTML/HTM files. Additionally, as shown in Figure 4, PDF files are the most stable files. In
McCown et al (2001), the most stable files were also PDF files.
Tajeddini, 0.; Azimi, A.; Sadatmoosavi, A. & Sharif-Moghaddam, H.
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Figure 4: Distribution of URLs by Type of File Formats
DISCUSSION
"URLs decay" phenomenon is a relatively new topic studied highly in recent years basically
because growing use of Web citations in scholarly papers (Zhao and Logan 2002; Maharan
et al. 2006). Considering the Internet as the first choice of researchers is not just because
of the added convenience of rapid information retrieval and sharing, but because it also
provides a means of making resources available that the printed media simply cannot
(Wren 2004). Therefore, even though the authors may appreciate the risk of future
inaccessibility of Web citations, they cannot easily avoid its use in their publications
(Falagas, Karveli and Tritsaroli 2008). In spite of web advantages, Web resources have led
us to a threatening challenge; citations are become decayed and disappeared.
The web citation decay rate was 34%. Previous studies reported the web citations decay as
50% (Germain 2000), 13% (Dellavalle et al. 2003), 45.4% (Casserly and Bird 2003), 39%
(Dimitrova and Bugeja 2007a), and 49.3% (Wagner et al. 2009). The decay was decreased
to 5% by adopting various strategies such as Google and Wayback Machine search, URL
path reduction or truncation, and manual editing. The main strategies which revived more
dead URLs were using the Google search (12%) and Wayback Machine (11%). Dimitrova
and Bugeja (2007b) showed that the Wayback Machine performance in reviving
unavailable URLs was largely better than the Google. They also showed that 64% of
citations retrieved through the Google were also found in the Wayback Machine and only
36% of citations were uniquely available through the Google. In contrast, 67% of the
citations found in the Wayback Machine did not overlap and 33% overlapped with the
Google.
Investigation through the URL top domains showed that the (org) has received more
citations than other domains. This finding was in agreement with Dimitrova and Bugeja
(2007) and McCown et al (2005) studies. PDF with 97% were the most stable file formats.
This was not in agreement with McCown et al (2005) study who reported HTML files as the
Death of Web Citations
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most stable format. There were three types of inaccessible web citations and the "file
error" was the most prevalent error for about 56% of inaccessible citations.
Ultimately, we faced with 5% absolutely unavailable web citations even with employing
useful services such as the Google, the Wayback Machine or the heuristic strategies. This
should be considered as an issue of using web citations. Checking the availability of web
citations prior to publishing submitted manuscripts could improve the availability status,
since the authors are likely more informed with their used web citations and simply can
modify the URL strings’ errors or replace decayed URLs with live alternatives.
CONCLUSION
Internet may prove to be an inhospitable medium (Dimitrova and Bugeja 2007), especially
for web-based research, because Web citations are speedily being used as well as
constantly fading away. Nevertheless, it should be accepted that Internet research is vital
to scholarship because the medium serves as a convenient electronic warehouse of data
accessible at all hours and in great quantities, thereby increasing the scope and breadth of
scholarship (Dimitrova and Bugeja 2007).
In current study we examined some strategies for recovering dead citations in hope for
patching the emerging hole in web citation area. However, in order to increase the rate of
availability of URLs, it has been already suggested that publishers, editors, and authors
should work together through:
a) Requiring authors to retain digital backup or printed copies of cited Internet-only
information to facilitate content recovery should a URL become unavailable;
b) Advocating the inclusion of web citations in an online archive;
c) Checking URLs systematically before publication to minimize unavailability due to
spelling errors or misprints (Wren et al. 2006; Dimitrova and Bugeja 2007).
In addition to the above recommendations using domains and files which are more stable
is recommended. As a solution to prevent decay or disappearance of Web citations and
diminish URLs decay use of Wayback Machine is recommended. According to Dimitrova et
al (2007), it is "a part of the Internet Archive, a nonprofit organization devoted to
preserving data, texts, audio, Web sites, and other digital materials since the early days of
the online revolution. Nonetheless it had some limitations. For example, the Wayback
Machine worked just for HTML based URLs. Therefore, we could not search the Wayback
Machine for the FTP (file transport protocol) based URLs. Also, this reputable internet
archive had some limitations in archiving dynamic pages and pages containing Java Scripts.
The Wayback Machine did not archive the pages which had not external links to other
websites. The Google was also unable to crawl the pages including active contents and
pages using robots.txt codes. Using heuristic rules were rather tedious. The user is not
always patient enough for manual editing of URL strings.
Citation decay means loss of data and this fact should be considered seriously for those
who especially work with online resources such as open access journals or other free
accessed materials on the web.
Tajeddini, 0.; Azimi, A.; Sadatmoosavi, A. & Sharif-Moghaddam, H.
Page | 28
ACKNOWLEDGEMENT
The authors would like to thank Dr. H. Dalili from (indicate his organizational affiliation) for
his helpful suggestions and valuable comments regarding this paper.
REFERENCES
Casserly, M. and Bird, J.E. 2003. Web citation availability: analysis and implications for
scholarship, College & Research Libraries, Vol. 64, no. 4: 300-317. Available at:
http://crl.acrl.org/content/64/4/300.full.pdf+html
Davis, P.M and Cohen, S.A. 2001. The effect of the web on undergraduate citation
behaviour 1996-1999. Journal of the American Society for Information Science and
Technology, Vol. 52, no. 4: 309-314.
Dellavalle, R.P., Drake, A., Graber, MC, and et al. (Provide names of all authors). 2003.
Going, going, gone: Lost Internet references. Science, Vol. 302, no. 5646: 787–88.
Available at: http://www.sciencemag .org/content/302/5646/787.full.pdf
Dimitrova, D.V. and Bugeja M. 2007. Raising the dead: recovery of decayed online
citations. American Communication Journal, Vol. 9, no. 2. Available at:
http://www.quosafulltext.com/sc_ddm/sc_ddm.jsp
Falagas, M.E., Karveli, E.A., and Tritsaroli, V.I. 2008. The risk of using the Internet as
reference resource: A comparative study. International Journal of Medical Informatics,
Vol. 77, no. 4: 280-286. Available at:
http://linkinghub.elsevier.com/retrieve/pii/S1386-5056(07)00124-4
Germain, C.A. 2000. URLs: Uniform Resource Locators or Unreliable Resource Locators.
College and Research Libraries, Vol. 61, no. 4: 359–65. Available at: http://crl.acrl.
org/content/61/4/359.full.pdf.
Goh, D.H., and Ng, P.K. 2007. Link decay in leading information science journals. Journal of
the American Society for Information Science and Technology, Vol.58, no. 1: 15-24.
Available at: http://onlinelibrary.wiley.com/doi/10.1002/asi.20513/pdf.
Harter, S.P. and Kim, H.J. 1996. Electronic journals and scholarly communication: a citation
and citation study. Information Research, Vol. 2, no. 1: 9. Available at:
http://InformationR.net/ir/2-1/paper9a.html
Klein, B. 2008. Google and the search for federal government information. Against the
Grain. Vol. 20, no. 2: 30-34. Available at: http://www.against-the-grain.com/TOCFiles
/20-2_Klein.pdf.
Koehler, W. 1999. An analysis of Web page and Web site constancy and permanence.
Journal of the American Society of information Science and Technology, Vol. 50, no. 2:
162-180.
Koehler, W. 2002. Web page change and persistence-a four-year longitudinal study.
Journal of the American Society of information Science and Technology, Vol. 53:162–
171. Available at: http://www.onlinelibrary.wiley.com/doi/10.1002/asi.10018/pdf .
Maharana, B., Nayak, K. and Sahu, N.K. 2006. Scholarly use of Web resources in LIS
research: a citation analysis. Library Review, Vol. 55, no. 9: 598-607. Available at:
http://www.emeraldinsight.com/journals.htm? articleid= 1576422.
McCown, F., Chan, S., Nelson, L.M., and Bollen, J. 2005. The availability and persistence of
web citations in D-Lib Magazine. Available at:
http://www.iwaw.net/05/papers/iwaw05-mccown1.pdf
Death of Web Citations
Page | 29
Rumsey, M. 2002. Runaway train: Problems of permanence, accessibility, and stability in
the use of web sources in law review citations. Law Library Journal, Vol. 94, no. 1: 27-
39. Available at: www.aall.org/products/pub_llj_v94n01/2002-02.pdf.
Spinellis, D. 2003. The decay and failures of web citations. CACM, Vol. 46, no. 1: 71–77.
Available at: http://www.dmst.aueb.gr/dds/pubs/jrnl/2003-CACM-
URLcite/html/urlcite.html
Tyler, D.C. and McNeil, B. 2003. Librarians and link rot: a comparative analysis with some
methodological considerations. Portal: Libraries and the Academy, Vol. 3, no. 4: 615–
32.
Wagner, C., Gebremichael, M.D., Taylor, M.KC, et al. (Provide all names). 2009.
Disappearing act: decay of uniform resource locators in health care management
journals. Journal of the Medical Library Association, Vol. 97, no. 2: 122-130. Available
at: http://www.ncbi.nlm. nih.gov/pmc/articles/PMC2670212/?tool =pubmed.
Wren, J.D. 2004. 404 not found: the stability and persistence of URLS published in
MEDLINE. Bioinformatics. Vol. 20, no. 5: 668-672. Available at: http://bioinformatics
.oxfordjournals.org/ content/20 /5/668.full.pdf+html.
Wren, J.D. 2008. URL decay in MEDLINE—a 4-year follow-up study. Bioinformatics, Vol.
24:1381-1385.
Wren, J.D., Johnson, K.R., Crockett, D.M, C, et al.(Provide all names). 2006. Uniform
resource locator decay in dermatology journals. Arch Dermatol, (Provide full name).,
Vol. 142: 1147-1152. Available at: http://archderm.ama-assn.org/cgi/reprint/142/9
/1147.pdf.
Zhang, Y. 1998. The impact of Internet based electronic resources on formal scholarly
communication in the area of library and information science: a citation analysis.
Journal of Information Science, Vol. 24, no. 4: 241–254. Available at:
http://jis.sagepub.com /content/24/4/24.1
Zhao, D.Z., and Logan, E. 2002. Citation analysis using scientific publication on the web as
data source: a case study in the XML research area. Scientometrics, Vol. 5, no. 3: 449-
472. Available at: http://www.springerlink.com/content/P212416833U25L83/
fulltext.pdf.
Zhiqiang, Wu. 2009. An empirical study of the accessibility of web citations in two Chinese
academic journals. Scientometric, Vol. 78, no. 3: 481-503. Available at:
http://www.springerlink.com/content/ dx77052378x8x203/fulltext.pdf
