1. Design considerations for an air-coupled phonocardiac microphone;Griffen,1969
2. Amplitude of sound vibrations from the canine heart and their attenuation by tissues;Feigen,1969
3. Electronic prototype for experimental development of a standardized phonocardiograph;MacCanon,1969
4. Luisada, A. A., MacCanon, D. M., Griffen, P. M., and Darrel, B.: Design and first results of a new phonocardiograph, Amer. J. Cardiol. (In press.)
5. The duration of normal heart sounds;Luisada;Brit. Heart J.,1949