1. Onishi, I., et al., Bull. Agric. Chem. Soc. Japan, 19, 137 (1955); 20, 61 (1956); 21, 38, 82, 177, 293 (1957); 22, 17 (1958).
2. Weybrew, J. A., and Stephens, R. L., Tobacco Sci., 6, 53 (1962).
3. Stedman, R. L., et al., Tobacco Sci., 7, 97 (1963).
4. Rowland, R. L., Latimer, R. H., and Giles, J. A., J. Amer. Chem. Soc., 78, 4680 (1956).
5. Erickson, R. E., Shank, C. H., Trenner, N. R., Arison, B. H., and Folkers, K., J. Amer. Chem. Soc., 81, 4999 (1959).