Drug use and treatment success among gang and non-gang members in El Salvador: a prospective cohort study
Substance Abuse Treatment Prevention and Policy (2013) - Comment
pubmed: 23734635  doi: 10.1186/1747-597x-8-20  issn: 1747-597x 

Knowlton W Johnson, Stephen R Shamblen, Matthew W Courser, Linda Young, Melissa H Abadi, Thom Browne