Roberts, P. (1970). The Roberts English series: A linguistics program. Harcourt, Brace & World.
Dyfyniad Arddull ChicagoRoberts, Paul. The Roberts English Series: A Linguistics Program. New York ; Chicago [etc.]: Harcourt, Brace & World, 1970.
Dyfyniad MLARoberts, Paul. The Roberts English Series: A Linguistics Program. Harcourt, Brace & World, 1970.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.