1. Abraham Manja, Cohen Peter, van Til Roelf-Jan, Langemeijer Marieke. Licit and illicit drug use in Amsterdam III. Developments in drug use 1987–1997. Amsterdam: CEDRO 1998. On-line: .
2. Abraham Manja, Cohen Peter, de Winter Marielle. Licit and illicit drug use in the Netherlands;Results of the first national drug use survey in the population of 12 years and older. Amsterdam: CEDRO 1999 (forthcoming).
3. Boekhout van Solinge Tim. The Swedish Drug Control System. An In-Depth Review and Analysis. Amsterdam: CEDRO/Mets, 1997.
4. Setting goals for drug policy: harm reduction or use reduction?;Caulkins;Addiction,1997
5. Cohen Peter. Cocaine use in Amsterdam in non deviant subcultures. Amsterdam: Department of Human Geography, University of Amsterdam, 1989. On-line: .