@misc{indiciaef7b03f5250f2,
  title = {Natural contraception using the Billings ovulation method.},
  author = {E Attar and S Gokdemirel and H Serdaroglu and A Coskun},
  year = {2002},
  url = {https://pubmed.ncbi.nlm.nih.gov/12201328/},
  note = {Source identifier: 12201328}
}