@book{135647,
	author = {Lang, Gerhard and Heiss, George D.},
	title = {A practical guide to research methods},
	publisher = {University Press of America},
	year = {c1984.},
	address = {Lanham, MD},
	edition = {3rd ed.},
	note = {Includes bibliographical references (p. 193-196) an index.}
}