1. Recording of pulse rate during exercise;BELL;J. Physiol.,1938
2. The cardiotachometer. An instrument to count the totality of heartbeats over long period of time;BOAS;Arch, intern. Med.,1928
3. A heart-rate recorder for biological experiments;BOYD;Electronic Engineering,1952
4. Continuous recording of the human heart-rate;BOYD;Electronic Engineering,1954
5. Sur la mesure instantanée de la fréquence du poulse;DJOURNO;Paris Méd.,1938