Costinett, S. (1985). Spectrum 5: A communicative course in english. Prentice Hall Regents.
Lua i Stíl Chicago (17ú heag.)Costinett, Sandra. Spectrum 5: A Communicative Course in English. London: Prentice Hall Regents, 1985.
Lua MLA (9ú heag.)Costinett, Sandra. Spectrum 5: A Communicative Course in English. Prentice Hall Regents, 1985.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.