1. AGAZZI, E. J., E. D. PETERS, and F. R. BROOKS: Anal. Chem.25, 237 (1953).
2. BONTOYAN, W. R.: J. Assoc. Offic. Agr. Chemists47, 255 (1964).
3. CHALLACOMBE, J. A., and J. A. McNULTY: Residue Reviews5, 57 (1964).
4. LISK, D. J.: Residue Reviews1, 152 (1962).
5. McNULTY, J. A.: Dohrmann Instruments Co. Personal communication, Apr. 25 (1966).