?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.au=Av%C5%9Far%2C+TS&rft.aufirst=TS&rft.aulast=Av%C5%9Far&rft.volume=21&rft.title=BMC+Pregnancy+Childbirth&rft.atitle=Health+outcomes+of+smoking+during+pregnancy+and+the+postpartum+period%3A+an+umbrella+review&rft.date=26+March+2021&rft.genre=article