@misc{indiciaefcf22009095a,
  title = {Algorithm for detecting the first and the second heart sounds by spectral tracking.},
  author = {A Iwata and N Ishii and N Suzumura and K Ikegaya},
  year = {1980},
  doi = {10.1007/bf02442475},
  url = {https://pubmed.ncbi.nlm.nih.gov/6991835/},
  note = {Source identifier: 6991835}
}