1. Algebraic Surfaces [in Russian], Vol. 75, Proc. V. A. Steklov Math. Inst. Acad. Sci. USSR (1965).
2. D. A. Gudkov, Usp. Mat. Nauk,29, No. 4, 3–79 (1974).
3. I. I. Pyatetskii-Shapiro and I. R. Shafarevich, Izv. Akad. Nauk SSSR, Ser. Mat.,35, 530–572 (1971).
4. J. Shah, Bull. Am. Math. Soc.,82, No. 5, 716–718 (1976).
5. V. M. Kharlamov, Funkts. Anal. Prilozhen.,10, No. 4, 55–68 (1976).