ชื่อเว็บไซค์

http://www.sema.go.th/node/2097

http://th.wikipedia.org/wiki/%E0%B8%84%E0%B8%A7%E0%B8%B2%E0%B8%A1%E0%B8%96%E0%B8%B5%E0%B9%88

http://www.sa.ac.th/winyoo/mechanicswave/Index.htm

http://www.rmutphysics.com/physics/oldfront/89/sound.html

http://www.rmutphysics.com/CHARUD/oldnews/146/science/waves.htm