[1] UNIV TEXAS,MED BRANCH,DEPT PREVENT MED & COMMUNITY HLTH,GALVESTON,TX 77550
[2] ICI PLC,CENT TOXICOL LAB,MACCLESFIELD SK10 YT1,CHESHIRE,ENGLAND
[3] AIN SHAMS UNIV,FAC MED,DEPT COMMUNITY ENVIRONM & OCCUPAT MED,CAIRO,EGYPT
[4] HOPE COLL,DEPT BIOL,HOLLAND,MI 49423