?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.au=Ong%2C+JS&rft.aufirst=JS&rft.aulast=Ong&rft.title=International+Journal+of+Epidemiology&rft.pages=1619-1630&rft.issn=1464-3685&rft.atitle=Association+of+vitamin+D+levels+and+risk+of+ovarian+cancer%3A+a+Mendelian+randomization+study&rft.date=October+2016&rft.issue=5&rft.volume=45&rft.genre=article