@article{harrell1996,
  title={MULTIVARIABLE PROGNOSTIC MODELS: ISSUES IN DEVELOPING MODELS, EVALUATING ASSUMPTIONS AND ADEQUACY, AND MEASURING AND REDUCING ERRORS},
  author={Frank E. Harrell and Kerry L. Lee and Daniel B. Mark},
  year={1996},
  journal={Statistics in Medicine},
  doi={10.1002/(sici)1097-0258(19960229)15:4<361::aid-sim168>3.0.co;2-4},
  url={https://doi.org/10.1002/(sici)1097-0258(19960229)15:4<361::aid-sim168>3.0.co;2-4}
}