@misc{indiciaee785f9c46df5,
  title = {Some epidemiological models with nonlinear incidence.},
  author = {H W Hethcote and P van den Driessche},
  year = {1991},
  doi = {10.1007/bf00160539},
  url = {https://pubmed.ncbi.nlm.nih.gov/2061695/},
  note = {Source identifier: 2061695}
}