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2. L. C. Herring, J. Urol. 88, 545 (1962).
3. K. Lonsdeil and D. S’yutor, Kristallografiya 16, 1210 (1971).
4. A. V. Golubchanskaya, Urologiya Nefrologiya, No. 3, 43 (1976).
5. M. Mebel’, G. Brin, and G. Shubert, in Science and Mankind (Znanie, Moscow, 1988), p. 35 [in Russian].