1. L. K. Romanova, In the book: Proceedings of the 3rd Conferences on Regeneration and Cell Multiplication [in Russian], p. 139, Moscow (1962).
2. N. V. Sanotskaya, Byull. éksp. Biol., No. 8, 40 (1960).
3. A. S. Spirin, Biokhimiya, No. 5, 656 (1958).
4. E. M. Albertini, A. Gori, and G. Pellegrini, Riv. Biol.,56, 317 (1963).
5. A. Dagradi, G. M. Candia, and O. Bellini, Chir. Pat. sper.,6, 801 (1958).