1. C. P. Stewart, S. L. Tompsett, andS. K. Niyogi, Clin. Chim. Acta6, 739 (1961).
2. I. Alwas, J. Derlikowski, A. B. Narbutt-Mering, E. Perkowski, andW. Weglowska, Acta Polon. Pharm.18, 357 (1961).
3. G. B. Marini-Bettol� andJ. A. Koch Frugoni, Rend. Ist. Super. Sanita.21, 319 (1958).
4. F. O. da Silveira, Tribuna Farm. (Brazil)24, 86 (1956).
5. R. Munier, Bull. soc. chim. biol.35, 1225 (1953).