@misc{indiciaeeeb4669e31ed,
  title = {Yellow-fever before smallpox vaccination.},
  author = {H J Friend},
  year = {1972},
  doi = {10.1016/s0140-6736(72)91895-8},
  url = {https://pubmed.ncbi.nlm.nih.gov/4115385/},
  note = {Source identifier: 4115385}
}