Warshawsky, D. (1983). Spectrum 3: A communicative course in english. Prentice Hall Regents.
Lua i Stíl Chicago (17ú heag.)Warshawsky, Diane. Spectrum 3: A Communicative Course in English. London: Prentice Hall Regents, 1983.
Lua MLA (9ú heag.)Warshawsky, Diane. Spectrum 3: A Communicative Course in English. Prentice Hall Regents, 1983.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.