Tietz, R. (1991). Complete Book of Effective Personal Letters: A Collection of over 400 Model Letters for almost every Form of Personal Correspondence. London: Prentice-Hall.
Dyfyniad Arddull ChicagoTietz, Robert. Complete Book of Effective Personal Letters: A Collection of Over 400 Model Letters for Almost Every Form of Personal Correspondence. London: Prentice-Hall, 1991.
Dyfyniad MLATietz, Robert. Complete Book of Effective Personal Letters: A Collection of Over 400 Model Letters for Almost Every Form of Personal Correspondence. London: Prentice-Hall, 1991.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.