von Elm, Erik BjörnErik Björnvon Elm2024-10-132024-10-132007https://boris-portal.unibe.ch/handle/20.500.12422/96451enCommentary: Assessing the quality of observational studies--or a lesson from Marsarticle10.7892/boris.227851759164100024909850003910.1093/ije/dym112