@misc{indiciae9009eaff0c51,
  title = {Second heart sound.},
  author = {A S Gooch},
  year = {1969},
  doi = {10.1056/nejm196905152802018},
  url = {https://pubmed.ncbi.nlm.nih.gov/5778432/},
  note = {Source identifier: 5778432}
}