@misc{indiciae91b624ce67e7,
  title = {A cardiotachometer which calculates rate digitally.},
  author = {V Elings and D Holly},
  year = {1973},
  doi = {10.1109/tbme.1973.324222},
  url = {https://pubmed.ncbi.nlm.nih.gov/4754321/},
  note = {Source identifier: 4754321}
}