RT Article T1 Cannabis versus other illicit drug use among methadone maintenance patients JF Psychology of addictive behaviors VO 10 IS 4 SP 222 OP 227 A1 Nirenberg, T. D. LA German YR 1996 UL https://krimdok.uni-tuebingen.de/Record/163915728X K1 Drogenkonsum K1 Methadonsubstitution