RT Article T1 Epidemiological estimates of risk in the process of becoming dependent upon cocaine: cocaine hydrochloride powder versus crack cocaine JF Psychopharmacology VO 172 IS 1 SP 78 OP 86 A1 Chen, Chuan-Yu A2 Anthony, James C. LA English YR 2004 UL https://krimdok.uni-tuebingen.de/Record/1912536943 DO 10.1007/s00213-003-1624-6