Article

Boumparis, Nikolaos and Karyotaki, Eirini and Schaub, Michael P and Cuijpers, Pim and Riper, Heleen (2017) Internet interventions for adult illicit substance users: a meta-analysis. Addiction , 112 , (9) , pp. 1521-1532.

Book

Korf, Dirk and Riper, Heleen, eds. (1997) Illicit drug use in Europe: proceedings of the Seventh Annual Conference on Drug Use and Drug Policy. Amsterdam: Korf and Riper .