Nash, E. L. (2000). Direct marketing: Strategy, planning, execution (4th ed.). New York: McGraw Hill.
Dyfyniad Arddull ChicagoNash, Edward L. Direct Marketing: Strategy, Planning, Execution. 4th ed. New York: McGraw Hill, 2000.
Dyfyniad MLANash, Edward L. Direct Marketing: Strategy, Planning, Execution. 4th ed. New York: McGraw Hill, 2000.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.