@conference{vrszegi1979professional, title = {Professional Line Output Level Electret Microphone for Public-Address Use}, author = {Várszegi, E. I. and Smallenberg, W. A. L.}, booktitle = {Audio Engineering Society Convention 62}, month = {Mar}, year = {1979}, url = {https://www.aes.org/e-lib/browse.cfm?elib=2899} }