@misc{indiciae438bcf35e387,
  title = {Observational studies for intervention assessment.},
  author = {H Comber and I J Perry},
  year = {2001},
  doi = {10.1016/s0140-6736(00)05219-3},
  url = {https://pubmed.ncbi.nlm.nih.gov/11467302/},
  note = {Source identifier: 11467302}
}