@misc{indiciaef789729d30dd,
  title = {P waves during ectopic atrial rhythms in man: a study utilizing atrial pacing with fixed electrodes.},
  author = {W A MacLean and R B Karp and N T Kouchoukos and T N James and A L Waldo},
  year = {1975},
  doi = {10.1161/01.cir.52.3.426},
  url = {https://pubmed.ncbi.nlm.nih.gov/1157240/},
  note = {Source identifier: 1157240}
}