@misc{indiciae2c0717be0559,
  title = {Letter: Book prices.},
  author = {J W Nicholas and J B Penfold},
  year = {1975},
  doi = {10.1016/s0140-6736(75)92856-1},
  url = {https://pubmed.ncbi.nlm.nih.gov/46980/},
  note = {Source identifier: 46980}
}