Sullivan, P. N., & Phong, G. Y. (1991). Super course for the TOELF. London: Prentice-Hall.
Dyfyniad Arddull ChicagoSullivan, Patricia N., và Grace Y.q Phong. Super Course for the TOELF. London: Prentice-Hall, 1991.
Dyfyniad MLASullivan, Patricia N., và Grace Y.q Phong. Super Course for the TOELF. London: Prentice-Hall, 1991.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.