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. Differences in the Validity of Self-Reported Drug Use Across Five Factors in Indianapolis, Fort Lauderdale, Phoenix, and Dallas, 1994 (ICPSR 2706) Rosay, Andre B.; University of Maryland at College Park; Herz, Denise C.