@article{Biggs2012,
author = {Biggs, M.A. and Karasek, D. and Foster, D.G.},
title= {Unprotected intercourse among women wanting to avoid pregnancy: Attitudes, behaviors, and beliefs},
year = {2012},
doi = {10.1016/j.whi.2012.03.003},
volume = {22},
number = {3},
pages = {311--318},
}