@misc{indiciaeafa83131cc21,
  title = {Graded exercise testing and postthoracotomy complications.},
  author = {P G Boysen and C A Clark and A J Block},
  year = {1990},
  doi = {10.1016/0888-6296(90)90449-p},
  url = {https://pubmed.ncbi.nlm.nih.gov/2131859/},
  note = {Source identifier: 2131859}
}