@article{fagen1962a, title = {A Figure of Merit for Horn Loudspeaker Drivers}, author = {Fagen, Edward A.}, journal = {J. Audio Eng. Soc}, volume = {10}, number = {4}, pages = {302--305}, year = {1962}, url = {https://www.aes.org/e-lib/browse.cfm?elib=837} }