Cita APA (7a ed.)

Warshawsky, D. (1983). Spectrum 4: A communicative course in English. Prentice Hall Regents.

Cita Chicago Style (17a ed.)

Warshawsky, Diane. Spectrum 4: A Communicative Course in English. London: Prentice Hall Regents, 1983.

Cita MLA (9a ed.)

Warshawsky, Diane. Spectrum 4: A Communicative Course in English. Prentice Hall Regents, 1983.