@misc{indiciae34e87019a755,
  title = {Cancer pain classification.},
  author = {R Twycross},
  year = {1997},
  doi = {10.1111/j.1399-6576.1997.tb04628.x},
  url = {https://pubmed.ncbi.nlm.nih.gov/9061097/},
  note = {Source identifier: 9061097}
}