1. N. N. Zhukov-Verezhnikov and M. I. Sokolov, In book: The prophylaxis of infections by living vaccines. [in Russian] Moscow, p. 14 (1960).
2. P. N. Kosyakov, Antigenic substances of the organism and their significance in biology and medicine. Moscow, p. 175 (1954).
3. G. W. Bird, Nature, Vol. 174, p. 1015 (1954).
4. Idem, Brit. med. Bull., Vol. 15, p. 165 (1959).
5. W. C. Boyd and R. M. Reguera, J. Immunol., Vol. 62, p. 333 (1949).