@article{kermack1927,
  title={A contribution to the mathematical theory of epidemics},
  author={W. O. Kermack and A. G. McKendrick},
  year={1927},
  journal={Proceedings of the Royal Society of London Series A Containing Papers of a Mathematical and Physical Character},
  doi={10.1098/rspa.1927.0118},
  url={https://doi.org/10.1098/rspa.1927.0118}
}