Percil, J., & Gray, J. (1988). Prospects: An advanced course teacher's book. Penguin Books.
芝加哥风格引文Percil, John, 与 Joanna Gray. Prospects: An Advanced Course Teacher's Book. London: Penguin Books, 1988.
MLA引文Percil, John, 与 Joanna Gray. Prospects: An Advanced Course Teacher's Book. Penguin Books, 1988.
警告：这些引文格式不一定是100％准确.