Siebert, F. S., & Peterson, T. (1956). Four theories of the press. University of Illinois Press.
Lua i Stíl Chicago (17ú heag.)Siebert, Fred S., agus Theodore Peterson. Four Theories of the Press. Urbana: University of Illinois Press, 1956.
Lua MLA (9ú heag.)Siebert, Fred S., agus Theodore Peterson. Four Theories of the Press. University of Illinois Press, 1956.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.