@misc{indiciae80da8dc18fa8,
  title = {Methodologic issues in observational studies.},
  author = {Arthur Hartz and J L Marsh},
  year = {2003},
  doi = {10.1097/01.blo.0000079325.41006.95},
  url = {https://pubmed.ncbi.nlm.nih.gov/12897594/},
  note = {Source identifier: 12897594}
}