@misc{indiciae710701e903e0,
  title = {P-wave changes in chronic obstructive pulmonary disease.},
  author = {J B Calatayud and J M Abad and N B Khoi and W W Stanbro and H M Silver},
  year = {1970},
  doi = {10.1016/0002-8703(70)90248-6},
  url = {https://pubmed.ncbi.nlm.nih.gov/4244706/},
  note = {Source identifier: 4244706}
}