Upward, C., & Davidson, G. (2011). The history of English spelling. Wiley-Blackwell.
Lua i Stíl Chicago (17ú heag.)Upward, Christopher, agus George Davidson. The History of English Spelling. Chichester, West Sussex, UK: Wiley-Blackwell, 2011.
Lua MLA (9ú heag.)Upward, Christopher, agus George Davidson. The History of English Spelling. Wiley-Blackwell, 2011.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.