Cita APA (7th ed.)

Abrams, S., Rein, D. P., & Byrd, D. R. H. (1993). Spectrum 2: A communicative course in english. Workbook 2A. Prentice-Hall.

Cita Chicago (17th ed.)

Abrams, Sharon, David P. Rein, i Donald R. H. Byrd. Spectrum 2: A Communicative Course in English. Workbook 2A. Englewood Cliffs: Prentice-Hall, 1993.

Cita MLA (9th ed.)

Abrams, Sharon, et al. Spectrum 2: A Communicative Course in English. Workbook 2A. Prentice-Hall, 1993.