os melhores
http://www.snarescience.com/articles/drum-head-vibration.php

http://www.drummerworld.com/forums/showthread.php?t=81521

https://www.reddit.com/r/Physics/comments/3napta/mathematics_of_drum_acoustics/

http://publications.lib.chalmers.se/records/fulltext/5768.pdf

http://www.acs.psu.edu/drussell/demos.html

http://physics.stackexchange.com/questions/22735/actually-hearing-the-shape-of-a-drum

https://courses.physics.illinois.edu/phys406/sp2016/Student_Projects/Spring14/Matthew_Fischer_Physics_406_Final_Project_Sp14.pdf