Hopper, P. J., & Traugott, E. C. (2003). Grammaticalization (2nd ed.). Cambridge University Press.
Lua i Stíl Chicago (17ú heag.)Hopper, Paul J., agus Elizabeth Closs Traugott. Grammaticalization. 2nd ed. Cambridge, UK, New York, NY: Cambridge University Press, 2003.
Lua MLA (9ú heag.)Hopper, Paul J., agus Elizabeth Closs Traugott. Grammaticalization. 2nd ed. Cambridge University Press, 2003.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.