Dyfyniad APA
Siebert, F. S., & Peterson, T. (1956). Four theories of the press. University of Illinois Press.
Dyfyniad Arddull Chicago
Siebert, Fred S., and Theodore Peterson. Four Theories of the Press. Urbana: University of Illinois Press, 1956.
Dyfyniad MLA
Siebert, Fred S., and Theodore Peterson. Four Theories of the Press. University of Illinois Press, 1956.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.