1. Official Methods of Analysis, Vol. 1, AOAC International, Arlington, VA, 15th ed., 1990, Ch. 10.
2. Pesticide Analytical Manual, Vol. I, US Food and Drug Administration, Washington, DC, 1991, Sec. 212.13a(2).
3. Pesticide Analytical Manual, Vol. I, US Food and Drug Administration, Washington, DC, 1991, Sec. 304E4.
4. Standard Methods of Analysis for Hygienic Chemists – With Commentary, Pharmaceutical Society of Japan, Tokyo, 2nd ed., 1990, p. 621.