Gairns, R., & Redman, S. (2003). Natural English: Upper-intermediate student's book. Oxford University Press.
芝加哥风格引文Gairns, Ruth, 与 Stuart Redman. Natural English: Upper-intermediate Student's Book. Oxford: Oxford University Press, 2003.
MLA引文Gairns, Ruth, 与 Stuart Redman. Natural English: Upper-intermediate Student's Book. Oxford University Press, 2003.
警告：这些引文格式不一定是100％准确.