Search Results Use the search box below to revise your search, or start a new search. Studies (2) Variables Publications Your query returned 2 studies. Sort by: Title A-Z Released/Updated Time Period Most Cited in ICPSR Bib. 1. Crack, Powder Cocaine, and Heroin: Drug Purchase and Use Patterns in Six Cities in the United States, 1995-1996 (ICPSR 2564) Riley, K. Jack 2. Estimating the Elasticities of Demand for Cocaine and Heroin with Data from 21 Cities from the Drug Use Forecasting (DUF) Program, 1987-1991 (ICPSR 6567) Caulkins, Jonathan P.