HP http://hyperphysics.phy-astr.gsu.edu/hbase/index.html
Physics Workd Magazine https://physicsworld.com/a/vibrating-drumheads-are-entangled-quantum-mechanically/
(1) (2) Benade, Arthur H. Fundamentals of Musical Acoustics. Ch 9, p143-144. Oxford University Press, 1976
(3) Stanford Digital Repository. Guide to the records of the Musical Acoustics Research
(4) (7) (41) Rossing, Thomas D. “The physics of kettledrums.” Scientific American 247/16 (November 1982): 172-178. Rossing, Thomas D., Craig A. Anderson, and Ronald I. Mills. “Acoustics of timpani.” Percussionist [Percussive Notes Research Edition] 19/3 (Fall 1982): 18-31. Rossing, Thomas D., Kvistad, Garry. “Acoustics of timpani: Preliminary studies.” Percussionist 13/3 (Spring 1976): 90-98. Christian, Richard S.; Davis, Robert E.; Tubis, Arnold; Anderson, Craig E.; Mills, Ronald. Rossing, Thomas D. Effects of air loading on timpani diaphragm vibration. Acoustical Society of America (Hg). in: Journal of the Acoustical Society of America (JASA). 76 Jg. No. 5. Woodbury, NY: 1984. S.1336-1345. Rossing, Thomas D. Science of Percussion Instruments. Singapore: World Scientific, 2000.
(5) Sullivan, Donald L. Accurate frequency tracking of timpani spectral lines. Acoustical Society OF America (Hg). in: Journal OF the Acoustical Society OF America (JASA). 101 Jg. No. 1. Woodbury, NY: 1997. S.530-538.
(6) Fleischer H. Fastl H. Universität der Bundeswehr München und TUM ISSN 1430-936X: Vibroakustische Untersuchungen an Paukenfellen. Fell, Kessel und Gestell der Orchesterpauke. Physikalische und gehörbezogene Analyse von Paukenklängen. Schriftenreihe: Beiträge zur Vibro und Psychoakustik.
(7) (9) (14) (17) Pennsylvania State University Acoustics Demo. “Vibrational Mode Shapes of a Circular Membrane.” acs.psu.edu. acs.psu.edu/drussell/demos/membranecircle/circle.html.
(8) WTT Pauken. “Membrane Modes.” wtt.pauken.org. wtt.pauken.org/chapter-2/membrane-modes-2.
(10) Georgia State University – HyperPhysics. “The Timpani.” HyperPhysics. hsc.edu.kw/…/music/timpani.html (replace with correct full link if available).
(11) Cook, John D. “Solving the Wave Equation on a Disk.” johndcook.com, 12 June 2021. johndcook.com/blog/2021/06/12/vibrating-circular-membranes.
(15) “Node (physics).” Wikipedia: The Free Encyclopedia, Wikimedia Foundation, en.wikipedia.org/wiki/Node_(physics).
(18) (23) (25) (33) (36) “Degenerate Modes of a Drum.” Euphonics, www.euphonics.org/degenerate-modes-of-a-drum/.
(19) (24) (26) (28) (30) (32) (34) (39) Worland, Randy, et al. “Normal Modes of a Musical Drumhead under Nonuniform Tension.” Journal of the Acoustical Society of America, vol. 127, no. 1, Jan. 2010, pp. 525–533. pubs.aip.org/asa/jasa/article/127/1/525/793705/.
(20) (27) (29) “Falstad Circular Membrane Simulator.” Falstad.com, www.falstad.com/circosc/directions.html
(21) (35) “Vibration of a Circular Membrane.” Wikipedia, en.wikipedia.org/wiki/Vibration_of_a_circular_membrane.
(22) (38) (41) “Degenerate Energy Levels.” Wikipedia, en.wikipedia.org/wiki/Degenerate_energy_levels.
(31) (37) (40) Hashimoto, Ryota, Yasuhiro Oikawa, and K. Yatabe. “Visualizing Mode Shape of a Drumhead under Non‑Uniform Tension.” Proceedings, 24th International Congress on Acoustics, 2022.