@book{3520,
	author = {Penny, R. K. and Gibbings, J. C.},
	title = {The experimental method :},
	publisher = {Longman ,},
	year = {c1974.},
	address = {London ;},
	note = {Label mounted on t.p.: Distributed in the U.S.A. by Longman, New York.}
}