1. I. M. Gel'fand and D. B. Fuks, "Cohomologies of the Lie algebra of vector fields on the circle," Funkts. Anal. Prilozhen.,2, No. 4, 92?93 (1968).
2. A. I. Kostrikin and I. P. Shafarevich, "Graded Lie algebras of finite characteristic," Izv. Akad. Nauk SSSR, Ser. Mat.,33, No. 2, 251?322 (1969).
3. N. N. Yakovlev, "The cohomology of Witt algebra," Funkts. Anal. Prilozhen.,9, No. 3, 95?96 (1975).
4. R. Block, "New simple Lie algebras of prime characteristic," Trans. Am. Math. Soc.,89, No. 2, 421?449 (1958).