@misc{indiciae2c081b6eb6e9,
  title = {[Family planning: "Billing's" ovulation method].},
  author = {M S Bhering and H Kajiyama},
  year = {1980},
  url = {https://pubmed.ncbi.nlm.nih.gov/6910749/},
  note = {Source identifier: 6910749}
}