@book{639,
	author = {Subrahmanyam, N. and Lal, Brij},
	title = {A textbook of sound /},
	publisher = {Vikas,},
	year = {c2005.},
	address = {New Delhi:},
	edition = {Rep.},
	note = {Includes references (p. 280- 281) and index.}
}