@conference{sano1978high, title = {High Efficiency Class A Audio Power Amplifier (Class A+ Amplifier)}, author = {Sano, Nobuya and Hayashi, Tomoyuki and Ogawa, Hidekazu}, booktitle = {Audio Engineering Society Convention 61}, month = {Nov}, year = {1978}, url = {https://www.aes.org/e-lib/browse.cfm?elib=2972} }