Melchior, Maria and Nakamura, Aurélie and Bolze, Camille and Hausfater, Félix and El Khoury, Fabienne and Mary-Krause, Murielle and Azevedo Da Silva, Marine (2019) Does liberalisation of cannabis policy influence levels of use in adolescents and young adults? A systematic review and meta-analysis. BMJ Open, 9, (7), e025880. https://bmjopen.bmj.com/content/9/7/e025880.