RT Article T1 Prevalence of youth substance use: The impact of methodological differences between two national surveys JF Drug and alcohol dependence VO 47 IS 1 SP 19 OP 30 A1 Gfroerer, Joseph 1954- A2 Kopstein, Andrea A2 Wright, Doug A. LA English YR 1997 UL https://krimdok.uni-tuebingen.de/Record/1912662256 DO 10.1016/S0376-8716(97)00063-X