Roberts, P. (1970). The Roberts English series: A linguistics program. Harcourt, Brace & World.
Lua i Stíl Chicago (17ú heag.)Roberts, Paul. The Roberts English Series: A Linguistics Program. New York ; Chicago [etc.]: Harcourt, Brace & World, 1970.
Lua MLA (8ú heag.)Roberts, Paul. The Roberts English Series: A Linguistics Program. Harcourt, Brace & World, 1970.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.