National Broadcasting Company. (1953). Why sales come in curves. National Broadcasting Co..
Cita Chicago (17th ed.)National Broadcasting Company. Why Sales Come in Curves. New York: National Broadcasting Co., 1953.
Cita MLA (8th ed.)National Broadcasting Company. Why Sales Come in Curves. National Broadcasting Co., 1953.
Atenció: Aquestes cites poden no estar 100% correctes.