1. Kertesz, Z. I., J. Amer. Chem. Soc., 61, 2544 (1939).
2. Jansen, E. F., and MacDonnel, L. R., Arch. Biochem., 8, 97 (1945).
3. Matus, J., Ber. Schweiz. Bot. Ges., 58, 319 (1948).
4. McColloch, R. J., and Kertesz, Z. I., Arch. Biochem., 17, 197 (1948).
5. Reid, W. W., Nature, 166, 76 and 569 (1950).