Não informado. (2008). School bell. National School Public Relations Association.
Lua i Stíl Chicago (17ú heag.)Não informado. School Bell. Washington: National School Public Relations Association, 2008.
Lua MLA (8ú heag.)Não informado. School Bell. National School Public Relations Association, 2008.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.