@misc{indiciaee181a94788b2,
  title = {Coital frequency and twinning.},
  author = {B Bønnelykke and J Olsen and J Nielsen},
  year = {1990},
  doi = {10.1017/s0021932000018526},
  url = {https://pubmed.ncbi.nlm.nih.gov/2335540/},
  note = {Source identifier: 2335540}
}