@misc{indiciae0fac07f1f936,
  title = {Observational studies.},
  author = {J F Peipert and M G Phipps},
  year = {1998},
  doi = {10.1097/00003081-199806000-00004},
  url = {https://pubmed.ncbi.nlm.nih.gov/9646956/},
  note = {Source identifier: 9646956}
}