"Models, Theoretical United States." . . "System analysis." . . "System analysis" . "Heroin addiction." . . "Heroin addiction" . "Analyse de systèmes." . . "Research design." . . "Research design" . "Drug and Narcotic Control United States." . . . . "Computers." . . "Computers" . "Drogue, Lutte contre la États-Unis." . . "Héroïnomanie." . . . . . . . . . . . . . . . . . . . . . . . . . . . . "The persistent poppy a computer-aided search for heroin policy"@en . . "The persistent poppy : a computer-aided search for heroin policy" . . . "Systèmes, Analyse de." . . "Heroin Dependence United States." . .