Epidemiology for the uninitiated. Aetiology of disease--selection of controls.
D002986:Clinical Trials as Topic; D003276:Contraceptives, Oral / Q000009:adverse effects; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D012959:Socioeconomic Factors; D013924:Thrombophlebitis / Q000139:chemically induced
D003276:Contraceptives, Oral