@misc{indiciae0203cccc093d,
  title = {A structural approach to selection bias.},
  author = {Miguel A Hernán and Sonia Hernández-Díaz and James M Robins},
  year = {2004},
  doi = {10.1097/01.ede.0000135174.63482.43},
  url = {https://pubmed.ncbi.nlm.nih.gov/15308962/},
  note = {Source identifier: 15308962}
}