Cita APA (7th ed.)

COWAN, D. (1968). Advertising in the 21st century: A model of advertising agency development during the next fifty years. Hutchinson.

Cita Chicago (17th ed.)

COWAN, D.S. Advertising in the 21st Century: A Model of Advertising Agency Development During the Next Fifty Years. London: Hutchinson, 1968.

Cita MLA (9th ed.)

COWAN, D.S. Advertising in the 21st Century: A Model of Advertising Agency Development During the Next Fifty Years. Hutchinson, 1968.