@book{51739,
	author = {Spence, Janet T.,},
	title = {Elementary statistics},
	publisher = {Appleton-Century-Crofts},
	year = {[1968]},
	series = {The Century Psychology Series},
	address = {New York},
	edition = {2 . ed.},
	note = {First ed. by B. J. Underwood and others.}
}