A check-list for observational research?
Vandenbroucke
J P
JP
D001172:Arthritis, Rheumatoid / Q000139:chemically induced; D003276:Contraceptives, Oral / Q000009:adverse effects; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D012106:Research
D003276:Contraceptives, Oral