@misc{indiciaedd695bb11a83,
  title = {Letter: if not, why not?},
  author = {B Williams},
  year = {1973},
  doi = {10.1016/s0140-6736(73)91070-2},
  url = {https://pubmed.ncbi.nlm.nih.gov/4126503/},
  note = {Source identifier: 4126503}
}