title: [Aspects of observational epidemiologic studies: case series, cross-sectional studies, environmental studies, case-control studies].
authors: Service d'hygiène, épidémiologie et prévention, hôpital Edouard-Herriot, Hospices civils de Lyon, 69437 Lyon Cedex 03, France.
authors: Thomas
authors: T
authors: Bénet
authors: Philippe
authors: P
authors: Vanhems
mesh_terms: D035843:Biomedical Research; D016021:Epidemiologic Studies; D006801:Humans; D011643:Publishing