1. Beauville, A.: Complex Algebraic Surfaces. London Mathematical Society Lecture note68 (1982)
2. Cossec, F.R.: Projective models of Enriques surfaces. Math. Ann.265, 283–334 (1983)
3. Mumford, D.: Abelian Varieties. Oxford Univesity Press (1970)
4. Mumford, D.: Varieties defined by quadratic equations. Questioni sulle varieta algebriche, Corsi dal C.I.M.E., Editioni Cremonese, Roma, 29–100 (1969)
5. Ramanan, S.: Ample divisors on abelian surfaces. Proc. of London Math. Soc.51, 231–245 (1985)