title: Travel and venous thrombosis: an exercise in thinking about bias.
authors: Jan P
authors: JP
authors: Vandenbroucke
authors: Suzanne C
authors: SC
authors: Cannegieter
authors: Frits R
authors: FR
authors: Rosendaal
mesh_terms: D006801:Humans; D012107:Research Design / Q000592:standards*; D018570:Risk Assessment; D015983:Selection Bias; D013997:Time Factors; D014195:Travel; D054556:Venous Thromboembolism / Q000209:etiology*