@misc{indiciae59d4f8e56434,
  title = {Derived variables for longitudinal studies.},
  author = {D R Cox and N Wermuth},
  year = {1999},
  doi = {10.1073/pnas.96.22.12273},
  url = {https://pubmed.ncbi.nlm.nih.gov/10535911/},
  note = {Source identifier: 10535911}
}