1. Berthelot (1859). Repert. Chim. appl., 1, 284.
2. Borsook, H. (1935). J. biol. Chem., 110, 481.
3. Brown, R. H., Duda, G. D., Korkes, S., and Handler, P. (1957).
4. Lubochinsky, B., and Zalta, J. P. (1954). Bull. Soc. Chim. biol., 36, 1363.
5. Thomas, P. (1912). Bull. Soc. Chim. Fr., ser. 4,11, 796.