@misc{indiciae087720c4a46d,
  title = {A compensation filter for chest portals.},
  author = {J A Purdy and D J Keys and F Zivnuska},
  doi = {10.1016/0360-3016(77)90135-3},
  url = {https://pubmed.ncbi.nlm.nih.gov/599073/},
  note = {Source identifier: 599073}
}