1. A. E. Voitenko, A. F. Demchuk, and B. I. Kulikov, Prib. Tekh. Éksp., No. 1, 250 (1976).
2. A. F. Demchuk, Candidate's Dissertation, Institute of Hydrodynamics, Siberian Branch, Academy of Sciences of the USSR (1971).
3. V. V. Bolotin, Prikl. Mekh.,8, No. 4, 3 (1972).
4. V. V. Bolotin, Prikl. Mat. Mekh.,23, No. 2, 362 (1963).
5. W. E. Baker and F. I. Allen, in: Proceedings of the Third U.S. National Congress on Applied Mechanics, ASME (1958), p. 79.