DP - MPI Library TY - JOUR T1 - Effectiveness and Cost-Effectiveness of Group versus Individual Motivational Enhancement for Substance Use T2 - International journal of group psychotherapy : official publication of the American Group Psychotherapy Association (formerly the American Group Therapy Association) SP - Vol. 62, No. 4 (2012), p. 655-661 CY - Philadelphia PY - 2012 ER -