Gude, K., & Duckworth, M. (1997). Proficiency masterclass. Oxford University Press.
Chicago Style (17th ed.) CitationGude, Kathy, and Michael Duckworth. Proficiency Masterclass. Oxford: Oxford University Press, 1997.
MLA (9th ed.) CitationGude, Kathy, and Michael Duckworth. Proficiency Masterclass. Oxford University Press, 1997.