Feldmann, H (September 1992). "[History of instrumental measuring of hearing acuity: the first acumeter]". Laryngo- Rhino- Otologie. 71 (9): 477–82. doi:10.1055/s-2007-997336. PMID1388477. S2CID260205193.
Feldmann, H (September 1992). "[History of instrumental measuring of hearing acuity: the first acumeter]". Laryngo- Rhino- Otologie. 71 (9): 477–82. doi:10.1055/s-2007-997336. PMID1388477. S2CID260205193.
Feldmann, H (September 1992). "[History of instrumental measuring of hearing acuity: the first acumeter]". Laryngo- Rhino- Otologie. 71 (9): 477–82. doi:10.1055/s-2007-997336. PMID1388477. S2CID260205193.
worldcat.org
Roeser, Ross J. (2013). Roeser's audiology desk reference (2nd ed.). New York: Thieme. ISBN9781604063981. OCLC704384422.