Cita APA (7th ed.)

Warshawsky, D. (1994). Spectrum 4: A communicative course in English. Workbook. Prentice Hall Regents.

Cita Chicago (17th ed.)

Warshawsky, Diane. Spectrum 4: A Communicative Course in English. Workbook. London: Prentice Hall Regents, 1994.

Cita MLA (9th ed.)

Warshawsky, Diane. Spectrum 4: A Communicative Course in English. Workbook. Prentice Hall Regents, 1994.