@misc{indiciaef38e9c4e2871,
  title = {Progestogen-only oral contraception and ectopic gestation.},
  author = {M Smith and M P Vessey and W Bounds and J Warren},
  year = {1974},
  doi = {10.1136/bmj.4.5936.104-c},
  url = {https://pubmed.ncbi.nlm.nih.gov/4415323/},
  note = {Source identifier: 4415323}
}