Doff, A., & Jones, C. (1997). Language in use: Upper-intermediate : self-study workbook with answer key (1st print.). Cambridge University Press.
Lua i Stíl Chicago (17ú heag.)Doff, Adrian, agus Christopher Jones. Language in Use: Upper-intermediate : Self-study Workbook with Answer Key. 1st print. Cambridge: Cambridge University Press, 1997.
Lua MLA (8ú heag.)Doff, Adrian, agus Christopher Jones. Language in Use: Upper-intermediate : Self-study Workbook with Answer Key. 1st print. Cambridge University Press, 1997.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.