@misc{indiciae8df015d6041e,
  title = {Identifiability and exchangeability for direct and indirect effects.},
  author = {J M Robins and S Greenland},
  year = {1992},
  doi = {10.1097/00001648-199203000-00013},
  url = {https://pubmed.ncbi.nlm.nih.gov/1576220/},
  note = {Source identifier: 1576220}
}