@book{21,
	author = {Dobler, Donald W. and Burt, David N.},
	title = {Purchasing and supply management :},
	publisher = {McGraw-Hill,},
	year = {1996.},
	address = {New York :},
	edition = {6th ed., international ed.},
	note = {Rev. ed. of: Purchasing and materials management. 5th ed. c1990.},
	url = {http://www.loc.gov/catdir/description/mh022/95036200.html}
}