Opening Pandora's box.
Petitti
D B
DB
D000022:Abortion, Spontaneous / Q000453:epidemiology*; D015982:Bias; D002140:California / Q000453:epidemiology; D005260:Female; D006801:Humans; D011247:Pregnancy; D012107:Research Design / Q000592:standards*; D014881:Water Supply / Q000592:standards*