Naterop, B. J., Haberfellner, E., & Weis, E. (1998). Business letters for all. New York: Oxford University press.
Dyfyniad Arddull ChicagoNaterop, Bertha J., Eva Haberfellner, và Erich Weis. Business Letters for All. New York: Oxford University press, 1998.
Dyfyniad MLANaterop, Bertha J., Eva Haberfellner, và Erich Weis. Business Letters for All. New York: Oxford University press, 1998.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.