@misc{indiciaeb52fe90d90fa,
  title = {Selection bias in epidemiologic studies.},
  author = {D G Kleinbaum and H Morgenstern and L L Kupper},
  year = {1981},
  doi = {10.1093/oxfordjournals.aje.a113113},
  url = {https://pubmed.ncbi.nlm.nih.gov/6971055/},
  note = {Source identifier: 6971055}
}