1. M. L. Petrunkin and A. M. Petrunkina, Practical Biochemistry. In Russian. Leningrad, 1951, pp. 346, 329.
2. V. Bisceglie, Bull. soc. chim. biol., 1950, t. 32, pp. 162–179.
3. Sydenstricker, cited from Bicknell, F. and Prescott, F. Vitamins, London, 1946.
4. C. E. Raiha and O. Forsander, Science, 1952, v. 115, pp. 242–243.
5. P. P. Foa, J. A. Smith and H. R. Weinstein, Nutr. Abstr. Rev., 1948, v. 17, No. 3, pp. 642–643.