1. M. S. Gordeeva, in: Cytological Mechanisms of Histogenesis [in Russian], Moscow (1979), p. 77.
2. M. S. Didukh, Byull. �ksp. Biol. Med., No. 12, 84 (1967).
3. M. S. Didukh and A. Ya. Friedenshtein, Tsitologiya, No. 7, 901 (1970).
4. A. G. Knorre, A Short Outline of Human Embryology [in Russian], Leningrad (1967).
5. A. N. Kurolesova and L. I. Afanasova, Ontogenez, No. 1, 94 (1978).