APA

Stevens R. E., Loudon D. L. & Warren W. E. (1991). Marketing planning guide. New York: Haworth Press.

Chicago

Stevens Robert E, Loudon David L and Warren William E. 1991. Marketing planning guide. New York: Haworth Press.

Harvard

Stevens R. E., Loudon D. L. and Warren W. E. (1991). Marketing planning guide. New York: Haworth Press.

MLA

Stevens Robert E, Loudon David L and Warren William E. Marketing planning guide. New York: Haworth Press. 1991.