@misc{indiciae559777197c42,
  title = {Instrumental variables: application and limitations.},
  author = {Edwin P Martens and Wiebe R Pestman and Anthonius de Boer and Svetlana V Belitser and Olaf H Klungel},
  year = {2006},
  doi = {10.1097/01.ede.0000215160.88317.cb},
  url = {https://pubmed.ncbi.nlm.nih.gov/16617274/},
  note = {Source identifier: 16617274}
}