[1] NORTH RHINE WESTPHALIA, FED STATE CONTROL LAB FOOD & ENVIRONM CHEM, W-4400 MUNSTER, GERMANY
[2] ERGO FORSCHUNGSGESELL MBH, W-2000 HAMBURG 50, GERMANY
[3] HANDI UNIV, COLL MED, HANOI, VIETNAM
[4] MINIST HLTH, HANOI, VIETNAM
[5] COLL MED, HO CHI MINH CITY, VIETNAM
[6] OBSTET & GYNECOL HOSP, HO CHI MINH CITY, VIETNAM
[7] INST ECOL TOXICOL, BAIKALSK, USSR
[8] INST ORTHOPED SURG, IRKUTSK, USSR
[9] VAJIRA METROPOLIS HOSP, BANGKOK, THAILAND
[10] HARVARD UNIV, MASSACHUSETTS GEN HOSP, SCH MED, DEPT SURG, BOSTON, MA 02114 USA