@misc{indiciae005c74b02030,
  title = {Second degree block within the bundle branches.},
  author = {N Cristal and W Ho},
  year = {1974},
  doi = {10.1378/chest.66.1.57},
  url = {https://pubmed.ncbi.nlm.nih.gov/4843600/},
  note = {Source identifier: 4843600}
}