SMITH, C. B., & WARDHAUGH, R. (1980). Signals. Macmillan.
Lua i Stíl Chicago (17ú heag.)SMITH, Carl B., agus ROnald WARDHAUGH. Signals. New York: Macmillan, 1980.
Lua MLA (9ú heag.)SMITH, Carl B., agus ROnald WARDHAUGH. Signals. Macmillan, 1980.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.