Gaya APA

Warshawsky, D. (1994). Spectrum : A communicative Course in English (2 Buku Edisi Terpisah). united states of america: Prentice Hall Regents.

Gaya MLA

Warshawsky, Diane. "Spectrum : A communicative Course in English". 2 Buku Edisi Terpisah united states of america: Prentice Hall Regents, 1994. Text.