References
- 1980 . Official Methods of Analysis, , 13th Ed. , Arlington, VA : AOAC . secs. 36.075–36.090
- Thompson , R. D. and Hoffmann , T. J. 1975 . J. Pharm. Sci. , 64 : 1863
- Holak , W. 1981 . J. Assoc. Off. Anal. Chem , 66 : 1203
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