Cita APA (7th ed.)

Center for Applied Linguistics & Shopen, T. (1987). Languages and their speakers. University of Pennsylvania Press.

Cita Chicago (17th ed.)

Center for Applied Linguistics i Timothy Shopen. Languages and Their Speakers. Philadelphia: University of Pennsylvania Press, 1987.

Cita MLA (9th ed.)

Center for Applied Linguistics i Timothy Shopen. Languages and Their Speakers. University of Pennsylvania Press, 1987.