Biber, D. (1999). Longman grammar of spoken and written English. Longman.
Lua i Stíl Chicago (17ú heag.)Biber, Douglas. Longman Grammar of Spoken and Written English. Harlow, Eng: Longman, 1999.
Lua MLA (9ú heag.)Biber, Douglas. Longman Grammar of Spoken and Written English. Longman, 1999.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.