@misc{indiciaec1470ee8f06c,
  title = {Pulse frequency meter.},
  author = {W LAWTON and N L WULFSOHN},
  year = {1958},
  doi = {10.1111/j.1365-2044.1958.tb08110.x},
  url = {https://pubmed.ncbi.nlm.nih.gov/13545561/},
  note = {Source identifier: 13545561}
}