Citazione Stile APA (7a Edizione)

Warshawsky, D., & Byrd, D. R. H. (1992). Spectrum: A communicative course in english: student book. Prentice Hall Regents Pearson Education.

Citazione stile Chigago Style (17a edizione)

Warshawsky, Diane, e Donald R. H. Byrd. Spectrum: A Communicative Course in English: Student Book. New Jersey, EUA: Prentice Hall Regents Pearson Education, 1992.

Citatione MLA (9a ed.)

Warshawsky, Diane, e Donald R. H. Byrd. Spectrum: A Communicative Course in English: Student Book. Prentice Hall Regents Pearson Education, 1992.