1. R. V. Petrov and L. S. Seslavina, Dokl. Akad. Nauk SSSR,176, No. 5, 1170 (1967).
2. V. F. Semenkov, Byull. Éksperim. Biol. i Med., No. 12, 78 (1967).
3. V. F. Semenkov, Dokl. Akad. Nauk SSSR,181, No. 6, 1514 (1968).
4. E. Jensen and M. Simonsen, Ann. New York Acad. Sci.,99, 657 (1962).
5. D. Michie and J. G. Howard, Ann. New York Acad. Sci., 99, 670 (1962).