@misc{indiciaee7ceb28def03,
  title = {Classification schemes for epidemiologic research designs.},
  author = {S Greenland and H Morgenstern},
  year = {1988},
  doi = {10.1016/0895-4356(88)90155-2},
  url = {https://pubmed.ncbi.nlm.nih.gov/3418359/},
  note = {Source identifier: 3418359}
}