@article{argy1969symbiotic, title = {-Symbiotic- R-Wave Monitor}, author = {Argy, Thomas W. and Greenbaum, William H.}, journal = {J. Audio Eng. Soc}, volume = {17}, number = {5}, pages = {550--553}, year = {1969}, url = {https://www.aes.org/e-lib/browse.cfm?elib=1554} }