Marketing 200: Marketing Mix

Truell, Allen D. "Marketing Mix." Encyclopedia of Business and Finance, 3rd ed., vol. 2, Macmillan Reference USA, 2014, pp. 518-522.

"The Four Ps (Marketing Mix)." Worldmark Global Business and Economy Issues, edited by Thomas Riggs, vol. 1: Business, Gale, 2015, pp. 111-117.