@misc{9523,
  author = {S. Jick and D. Pennap},
  title = {Drospirenone- and levonorgestrel-containing oral contraceptives and the risk of gallbladder disease},
  year = {2012},
  journal = {Contraception},
  volume = {86},
  number = {3},
  pages = {220-3},
  issn = {0010-7824},
  doi = {10.1016/j.contraception.2012.01.006},
}