1. L. I. Aruin, B. Z. Chikunova, and I. E. Trubitsyna, in: Current Problems in Gastroenterology [in Russian], Vol. 2, No. 9, 97 (1976).
2. T. B. Timashkevich, Ways and Mechanisms of Regeneration of the Digestive Tract in Vertebrates [in Russian], Moscow (1978).
3. H. M. Adair, J. Anat. (London),125, 401 (1978).
4. T. E. Hunt, Anat. Rec.,131, 193 (1958).
5. E. Myhre, Arch. Path.,69, 314 (1960).