Obee, B. (1998). Cambridge first certificate: Grammar and usage. Cambridge University Press.
Dyfyniad Arddull ChicagoObee, Bob. Cambridge First Certificate: Grammar and Usage. Cambridge: Cambridge University Press, 1998.
Dyfyniad MLAObee, Bob. Cambridge First Certificate: Grammar and Usage. Cambridge University Press, 1998.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.