Warshawsky, D. (1994). Spectrum 4: A communicative course in English. Workbook. Prentice Hall Regents.
Cita Chicago Style (17a ed.)Warshawsky, Diane. Spectrum 4: A Communicative Course in English. Workbook. London: Prentice Hall Regents, 1994.
Cita MLA (9a ed.)Warshawsky, Diane. Spectrum 4: A Communicative Course in English. Workbook. Prentice Hall Regents, 1994.
警告：这些引文格式不一定是100％准确.