Armstrong, G., & Kotler, P. (2009). Marketing: An introduction (9th ed.). Pearson/Prentice Hall.

Armstrong, Gary, and Philip Kotler. Marketing: An Introduction. 9th ed. Upper Saddle River, NJ: Pearson/Prentice Hall, 2009.

Armstrong, Gary, and Philip Kotler. Marketing: An Introduction. 9th ed. Pearson/Prentice Hall, 2009.