1. Wogan, G., Fed. Proc., 27, 932 (1968).
2. Engebrecht, R. H., Ayres, J. L., and Sinnhuber, R. O., J. Assoc. Offic. Anal. Chem., 48, 815 (1965).
3. J. Assoc. Offic. Anal. Chem., 49, 229 (1966).
4. Pons, W. A., jun., and Goldblatt, L. A., J. Amer. Oil Chem. Soc., 42, 471 (1965).
5. Lijinsky, W., and Butler, W. H., Proc. Soc. Exp. Soc. Med., 123, 161 (1966).