Effective treatment of homeless substance abusers The role of contingency management
Schumacher, JE., Milby, JB., McNamara, CL., Wallace, D., Michael, M., Popkin, S., & Usdan, S. (1999). Effective treatment of homeless substance abusers: The role of contingency management. In ST. Higgins, & K. Silverman (Eds.), Motivation Behavior Change Among Illicit-Drug Abusers: Research on Contingency Managment Interventions Washington, DC: American Psychological Association.