[1] Univ Connecticut, Dept Sociol, Storrs, CT 06269 USA
[2] ABT Associates Inc, Cambridge, MA 02138 USA
[3] Abt Associates Inc, Ho Chi Minh City, Vietnam
[4] Guangxi Ctr Dis Control, Ctr HIV AIDS Prevent & Control, Nanning, Peoples R China
[5] Ha Giang Prov Hlth Serv, Ha Giang, Vietnam
[6] Abt Associates Inc, Hanoi, Vietnam
[7] Univ Alabama, Tuscaloosa, AL 35487 USA
[8] Beth Israel Deaconess Med Ctr, Inst Chem Dependency, New York, NY 10003 USA