@misc{indiciae36c9e4483ce9,
  title = {Ballistocardiographic waveform - some contributing factors.},
  author = {Graybiel, A. and Jackson, D. H. and Mitchell, R. E. and Oberman, A.},
  year = {1967},
  url = {https://ntrs.nasa.gov/citations/19680094720},
  note = {Source identifier: 19680094720}
}