@misc{indiciae5670e0e0e3cf,
  title = {Inference using conditional logistic regression with missing covariates.},
  author = {S R Lipsitz and M Parzen and M Ewell},
  year = {1998},
  url = {https://pubmed.ncbi.nlm.nih.gov/9544523/},
  note = {Source identifier: 9544523}
}