... Res. 15 (2008) (Abdulkadri andAjibefun, 1998), (Adams, 1993), (Ademosun, 1980), (Ademosun, 1982a), (Ademosun, 1982b), (Ademosun, 1996), (Aderinola et al., 1997), (Agbonlahor et al., 2003, (Akatugba-Ogisi, 1994), (Allison-Oguru, 2004), (Allison-Oguru et al., 2006), (Amadi, 1978), (Amoo, 1992), (Amoo and Smith, 1996), (Berg, 2001), (Carter, 1997), (Daramola and Aiyesan, 1990), (Fogg, 1965), (Gobin et al., 2001), (Goldman and Smith, 1995), (Jabbar et al., 1992), ( Jabbar et al., 2002), (Kormawa and Oppen, 2001), (Kushwaha and Ochi, 1999), (Lakshmanan, 1982), (Langyintuo et al., 2005), (Lawal and Ibrahim, 2007), (Omoregie and Thomson, 2001), (Onyenwaku et al., 1983), (Osayimwese, 1974), (Salami and Ilori, 1998), (Sanni et al., 2003), , (Smith, 1974), (Smock, 1969), (Tre and Lowenberg-Deboer, 2005), (Verinumbe et al., 1985). (Adenikinju et al., 2002), (Akinyosoye, 1995), (Anandarajan et al., 2000), (Beugre´and Offodile, 2001), (Carter, 1997), (Ehie and Smith, 1994a), (Ehie and Smith, 1994b), (Ehikhamenor, 2003), (Foster, 1986), (Habeeb, 1991), (Idowu et al., 2002), (Jabbar et al., 2002), (Msheliza, 1991), (Nyong, 1989), (Ogbu, 1996), (Ogbu and Smith, 1990), (Smith and Ogbu, 1994), (Soyibo et al., 1990), (Soyibo et al., 1991), (Thomas and Adams, 1999). (Adekola and Ishaya, 1989). ...