Kotler, Philip. Marketing : an introduction / Philip Kotler, Gary Armstrong. - 2nd ed. - Englewood Cliffs, N.J. : Prentice-Hall, c1990. - xxiv, 592 p. : ill. (some col.) ; 29 cm. ISBN: 0135564085 LCCN: 89022881 LC Class. No.: HF5415 .K625 1990 / .K625 1990 Dewey Class. No.: 658.8