@book{15629,
	author = {Ryan, William T.},
	title = {A guide to marketing /},
	publisher = {Learning Systems Co.,},
	year = {c1981.},
	series = {Irwin publications for professional development},
	address = {Homewood ; Ill. :},
	note = {"An adaptation of material previously published in a programmed learning aid (PLAID) entitled Principles of marketing.}
}