@misc{indiciaefbdd3bfcecb2,
  title = {The atriogram: a bedside method for recording high gain P waves.},
  author = {N Cristal and L Freidberg},
  year = {1974},
  doi = {10.1378/chest.65.5.554},
  url = {https://pubmed.ncbi.nlm.nih.gov/4826030/},
  note = {Source identifier: 4826030}
}