Doff, A., & Jones, C. (1997). Language in use: Upper-intermediate : self-study workbook with answer key (1st print.). Cambridge University Press.
Chicago-Zitierstil (17. Ausg.)Doff, Adrian, und Christopher Jones. Language in Use: Upper-intermediate : Self-study Workbook with Answer Key. 1st print. Cambridge: Cambridge University Press, 1997.
MLA-Zitierstil (8. Ausg.)Doff, Adrian, und Christopher Jones. Language in Use: Upper-intermediate : Self-study Workbook with Answer Key. 1st print. Cambridge University Press, 1997.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.