@misc{indiciaefadfbec636ee,
  title = {Precordial calibration.},
  author = {Z Z Zao},
  year = {1972},
  doi = {10.1016/s0022-0736(72)80069-4},
  url = {https://pubmed.ncbi.nlm.nih.gov/5030654/},
  note = {Source identifier: 5030654}
}