A phonocardiogram (or PCG) is a plot of high-fidelity recording of the sounds and murmurs made by the heart with the help of the machine called the phonocardiograph; thus, phonocardiography is the recording of all the sounds made by the heart during a cardiac cycle.[2][3]
^Silverman, Mark E.; Fleming, Peter R.; Hollman, Arthur; Julian, Desmond G.; Krikler, Dennis M. (2012-12-06). British Cardiology in the 20th Century. Springer Science & Business Media. ISBN9781447107736.Chapter 8/no Google page given