@book{170558,
	author = {Sall, John P. and Allen, Alice T., ed. },
	title = {SAS language guide for personal computers, version 6 edition  /},
	publisher = { SAS Institute,},
	year = {1985},
	address = {Estados Unidos de América  :},
	edition = {6a ed.},
	note = {Es material fotocopiado}
}