Kleppner, O., & Govoni, N. A. P. (1988). Advertising procedure (10th ed.). Prentice-Hall.
Dyfyniad Arddull ChicagoKleppner, Otto, and Norman A. P. Govoni. Advertising Procedure. 10th ed. Englewood Cliffs, N.J: Prentice-Hall, 1988.
Dyfyniad MLAKleppner, Otto, and Norman A. P. Govoni. Advertising Procedure. 10th ed. Prentice-Hall, 1988.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.