Clarke , D. (1970). Modern English Practice. Longman Green.
Lua i Stíl Chicago (17ú heag.)Clarke , D. Modern English Practice. London: Longman Green, 1970.
Lua MLA (9ú heag.)Clarke , D. Modern English Practice. Longman Green, 1970.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.