Tyndall, John (1915). Sound. New York: D. Appleton & Co. p. 156.
doi.org
dx.doi.org
Feldmann, H. (1997). "History of the tuning fork. I: Invention of the tuning fork, its course in music and natural sciences. Pictures from the history of otorhinolaryngology, presented by instruments from the collection of the Ingolstadt German Medical History Museum". Laryngo-rhino-otologie76 (2): 116–22. doi:10.1055/s-2007-997398. பப்மெட்:9172630.
nih.gov
ncbi.nlm.nih.gov
Feldmann, H. (1997). "History of the tuning fork. I: Invention of the tuning fork, its course in music and natural sciences. Pictures from the history of otorhinolaryngology, presented by instruments from the collection of the Ingolstadt German Medical History Museum". Laryngo-rhino-otologie76 (2): 116–22. doi:10.1055/s-2007-997398. பப்மெட்:9172630.