@book{176117,
	author = {United Nations.},
	title = {Towards a system of social and demographic statistics /},
	publisher = {United Nations,},
	year = {1975.},
	series = {Studies in methods ; ser. F, no. 18},
	address = {New York :},
	note = {"United Nations publication : Sales no. E.74.XVII.8."}
}