@book{250,
	author = {Harnett, Donald L},
	title = {Statistical methods for business and economics / Donald L. Harnett, Ashok K. Soni.},
	publisher = {Reading, Mass. : Addison-Wesley Pub. Co., c1991.},
	address = {Reading, Mass. : Addison-Wesley Pub. Co., c1991.},
	edition = {4th ed.}
}