Keller, R., & Duenwald, K. (1998). A theory of linguistic signs. Oxford University Press.
Lua i Stíl Chicago (17ú heag.)Keller, Rudi, agus Kimberley Duenwald. A Theory of Linguistic Signs. Oxford: Oxford University Press, 1998.
Lua MLA (9ú heag.)Keller, Rudi, agus Kimberley Duenwald. A Theory of Linguistic Signs. Oxford University Press, 1998.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.