1. Y. TAKENOBU et al., Jap. J. Pub. Health (in Japanese).,119, 5320 (1972).
2. U.S. Public Health Service. Drinking Water Standards-1962., Public Health Service Pub. (1963).
3. J. W. SMITH., Organic Compounds in Aquatic Environments., Marcel Dekker, INC. New York. 95 (1971).
4. W.C. HUEPER and C.C. RUCHHOFT., Arch. Ind. Occup. Med.,9, 488 (1954)
5. Standard Methods for the Examination of Water and Wastewater., 12th ed., Amer. Public Health Assoc., New York (1965).