@phdthesis{ Solr-1122143311, title = {Changes in internal - external control expectancies and future time perspective of narcotic addicts in a methadone maintenance treatment program}, author = {Henik, Willy}, address = {Ann Arbor, Mich.}, publisher = {Univ. Microfilms}, year = {1974}, school = {Zugl.: Fordham Univ., Diss., 1972}, }