@book{1564,
	author = {Scheaffer, Richard l},
	title = {Elementary survey sampling / Richard L.Scheaffer, William Mendenhall, Lyman Ott.},
	publisher = {Boston : PWS-KENT Pub. Co., 1990.},
	address = {Boston : PWS-KENT Pub. Co., 1990.},
	edition = {4th ed.}
}