@article{cooper1972discrete, title = {Discrete-Matrix Multichannel Stereo}, author = {Cooper, Duane H. and Shiga, Takeo}, journal = {J. Audio Eng. Soc}, volume = {20}, number = {5}, pages = {346--360}, year = {1972}, url = {https://www.aes.org/e-lib/browse.cfm?elib=2070} }