@misc{indiciaeb72a8f635888,
  title = {Sonar: What it can and cannot do in obstetrics.},
  author = {I Donald},
  year = {1974},
  doi = {10.1177/003693307401900501},
  url = {https://pubmed.ncbi.nlm.nih.gov/4415841/},
  note = {Source identifier: 4415841}
}