@book{36107,
	author = {Langhammer, Rolf J. and Hiemenz, Ulrich.},
	title = {Regional integration among developing countries :},
	publisher = {Trade Policy Division, World Bank,},
	year = {[1991]},
	series = {UNDP-World Bank Trade Expansion Program occasional paper ;},
	address = {Washington, D.C. :},
	note = {"December 1991."}
}