@misc{indiciaea5e108491592,
  title = {Heart tone.},
  author = {G E Burch and T D Giles},
  year = {1970},
  doi = {10.1016/0002-8703(70)90322-4},
  url = {https://pubmed.ncbi.nlm.nih.gov/4312332/},
  note = {Source identifier: 4312332}
}