Butterfield, J. (2007). Oxford A-Z of English usage. Oxford University Press.
Lua i Stíl Chicago (17ú heag.)Butterfield, Jeremy. Oxford A-Z of English Usage. Oxford: Oxford University Press, 2007.
Lua MLA (9ú heag.)Butterfield, Jeremy. Oxford A-Z of English Usage. Oxford University Press, 2007.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.