THCi - The Honest Cannabis Information Foundation
Some things every visitor needs to know. You don't want to accidentally eat "space cake" and coffee as just a morning snack.

Mind's High
Nicely designed site about knowledge and emotion in relationship to drug usage.

CEDRO
Centre for Drug Research, University of Amsterdam combines epidemiological and longitudinal research on illicit drugs, addiction theory, and drug policy developments in Europe.

Trimbos-instituut
The Netherlands Institute of Mental Health and Addiction, aims to promote mental health in the broadest sense of the term.