@conference{sakai1985digital, title = {Digital-to-Analog Conversion by Piezoelectric Headphone}, author = {Sakai, Shinichi and Kyouno, Noboru and Fujiwara, Susumu}, booktitle = {Audio Engineering Society Convention 78}, month = {May}, year = {1985}, url = {https://www.aes.org/e-lib/browse.cfm?elib=11524} }