1. Henskens, R. (2004). Grab and hold: randomized controlled trial of the effectiveness of an outreach treatment program for chronic, high-risk crack abusers. Tilburg: Academisch proefschrift Universiteit van Tilburg.
2. Henskens, R., Mulder, C.L., Garretsen, H., Bongers, I., & Sturmans, F. (2005). Gender differences in problems and needs among chronic, high-risk crack abusers: results of a randomized controlled trial. Journal of Substance Use, 10, 128-140.
3. Henskens, R., Garretsen, H., Bongers, I., Van Dijk, A., Sturmans, F. (2005). Effectiveness of an outreach treatment program for inner city crack abusers: compliance, outcome, and client satisfaction. Accepted for publication in Substance Use and Misuse.
4. Henskens, R., Garretsen, H., Bongers, I., Mulder, C.L., & Kroon, H. (2005). Fidelity of an outreach treatment program for chronic crack abusers in the Netherlands to the ACT model. Psychiatric services, 56, 1451 -1454.
5. Kokkevi, A., & Hartgers, C. (1994). European Addiction Severity Index; handleiding voor de training en afname van EuropAsi vraaggesprekken. Amsterdam: AIAR.