Pischke, Claudia Ruth; Helmer, S. M.; Pohlabeln, H.; Muellmann, S.; Schneider, S.; Reintjes, R.; Schmidt-Pokrzywniak, A.; Girbig, M.; Krämer, Alexander ; Icks, A.; Walter, U.; Zeeb, Hajo: Effects of a Brief Web-Based "Social Norms"-Intervention on Alcohol, Tobacco and Cannabis Use Among German University Students: Results of a Cluster-Controlled [...]. In: Frontiers in Public Health. Jg.9. 2021