APA (7e ed.) Bronvermelding

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

Chicago (17e ed.) Bronvermelding

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

MLA (9e ed.) Bronvermelding

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