@book{7241,
	author = {Cassel, Claes, and Särndal, Carl-Erik,},
	title = {Foundations of inference in survey sampling /},
	publisher = {Wiley,},
	year = {c1977.},
	series = {Wiley series in probability and mathematical statistics},
	address = {New York :},
	note = {Includes index.}
}