Whitney, N. (1994). Open doors (student's book 1): Có sách. Oxford: Oxford University Press.
Trích dẫn kiểu ChicagoWhitney, Norman. Open Doors (student's Book 1): Có Sách. Oxford: Oxford University Press, 1994.
MLA CitationWhitney, Norman. Open Doors (student's Book 1): Có Sách. Oxford: Oxford University Press, 1994.
Advarsel: Disse citationer er muligvist ikke 100% nøjagtige.