Crystal, D. (1988). The english language. Penguin Books.
Lua i Stíl Chicago (17ú heag.)Crystal, David. The english Language. Penguin Books, 1988.
Lua MLA (8ú heag.)Crystal, David. The english Language. Penguin Books, 1988.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.