1. M. Nagata, ?Rational surfaces. 1,? Matematika,8, No. 1, 55?72 (1964).
2. M. Demazure, ?Surfaces Del Pezzo II, III, IV, V,? Lect. Notes Math.,777, 23?70 (1980).
3. I. R. Shafarevich et al., Algebraic Surfaces [in Russian], Memoirs of the Math. Inst., Academy of Sciences of the USSR, Vol. 75 (1965).
4. Yu. I. Manin, Cubic Forms [in Russian], Nauka, Moscow (1972).
5. Yu. I. Manin, ?Rational surfaces over perfect fields,? Publ. Math. IHES,30, 55?113 (1966).