Oxenden, C. (2009). American English file: Workbook 4. Oxford: Oxford University Press.
Dyfyniad Arddull ChicagoOxenden, Clive. American English File: Workbook 4. Oxford: Oxford University Press, 2009.
Dyfyniad MLAOxenden, Clive. American English File: Workbook 4. Oxford: Oxford University Press, 2009.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.