8[1]Julian M.Alston,Raymond J.Yenner,The effects of the US Plant Variety Protection Act on wheat genetic improvement,Research Policy 31(2002)527-542,www.elsevier.com/locate/econbase
9[2]Gokhan Ozertan,Intellectual Property Rights Protection of Reproduclble Biotechnology Innovation,dissertation of Bogazici University? Istanbul Turkey,December 2001