?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.au=Geary%2C+RS&rft.aulast=Geary&rft.aufirst=RS&rft.issue=9&rft.title=BMJ+Open&rft.date=26+September+2016&rft.issn=2044-6055&rft.atitle=Actual+and+preferred+contraceptive+sources+among+young+people%3A+findings+from+the+British+National+Survey+of+Sexual+Attitudes+and+Lifestyles.&rft.volume=6&rft.genre=article