1. B. A. Kazansky and N. F. Glushnev, Bull. Acad. Sci. USSR, Chemical Series, 1938, 1065.
2. S. David, G. Dupont and C. Paquot, Bull. Soc. Chim. (5), 11, 561 (1944).
3. H. R. Arnold and J. A. Carnahan. U.S. Patent 2584531; C. A. 46, 7579 (1952),
4. J. F. Eijkman, Chemisch Weekblad 1, 7 (1903);
5. Chem. Zentr. 1903, 2, 982.