1. BIROS,F.J., A.C.WALKER, A.MEDBERY: Bull. Environ. Contam. Toxicol.5, 317 (1970).
2. JENSEN, J., A.G. JOHNELS, M. OLSSON, G. OTTERLIND: Nature224, 247 (1969).
3. MASUDA,Y., R.KAGAWA, M.KURATSUNE: Fukuoka Igaku Zasshi65, 25 (1974).
4. MATSUDA,H., T.SHIMAMOTO, Y.MORI, M.WATANABE: Annual Report of Ehime Prefec. Inst. Public Health36, 30 (1974).
5. MIZUTANI,T., M.MATSUMOTO, K.FUJIWARA: Igakuno Ayumi81, 666 (1972).