Obee, B. (1998). Cambridge first certificate: Grammar and usage. Cambridge University Press.
芝加哥风格引文Obee, Bob. Cambridge First Certificate: Grammar and Usage. Cambridge: Cambridge University Press, 1998.
MLA引文Obee, Bob. Cambridge First Certificate: Grammar and Usage. Cambridge University Press, 1998.
警告：这些引文格式不一定是100％准确.