Causation, bias and confounding: a hitchhiker's guide to the epidemiological galaxy. Part 1. Principles of causality in epidemiological research: time order, specification of the study base and specificity.
作者信息
Shapiro Samuel
机构信息
Department of Epidemiology, University of Cape Town, Cape Town, South Africa.
出版信息
J Fam Plann Reprod Health Care. 2008 Apr;34(2):83-7.