@article{charlson1987-3558716,
  author  = {Charlson, Mary E. and Pompei, Peter and Aleš, Kathy L. and MacKenzie, C. Ronald},
  title   = {{A new method of classifying prognostic comorbidity in longitudinal studies: Development and validation}},
  journal = {Journal of Chronic Diseases},
  year    = {1987},
  doi     = {10.1016/0021-9681(87)90171-8},
  pmid    = {3558716},
  url     = {https://doi.org/10.1016/0021-9681(87)90171-8}
}