Veerle Van Den Eeckhout’s research while affiliated with Leiden University and other places

... In the context of the maxim lex specialis derogat legi generali, Martii Koskenniemi expressed the view that, in practice, treaties are o en considered as lex specialis vis-à-vis international custom and general principles of law.²¹ The Study Group's conclusions further explained that general principles (34)(35)(36)(37)(38). According to the Professor, the Court did not decide whether the general principles of law are common to the legislation and practice of States, or whether they are general principles of international law. ...

Reference:

General Principles of Law at the Turn of Civilisations

... The notion of interpersonal human rights is admittedly innovative, but at least to some extent, it seems to be in the cards; it resonates with some recent developments of transnational law, at both the national and the (public) international levels, which provide (respectively) for the extraterritorial application of certain interpersonal obligations and the extension of state obligations to non-state parties. 40 Defending this conception of interpersonal human rights and its significance to transnational private law is beyond the scope of this article. 41 For my purpose of defending the moderate interpretation of the EU's regulatory private law, it is enough to appreciate the importance of rethinking private law as a legal category whose significance is, if anything, increasing in our transnational era. ...

Reference:

Between Regulatory and Autonomy-Based Private Law