Covey, S. R. (1991). Principle-Centred Leadership. Pocket Books.
芝加哥风格引文Covey, Stephen R. Principle-Centred Leadership. London: Pocket Books, 1991.
MLA引文Covey, Stephen R. Principle-Centred Leadership. Pocket Books, 1991.
警告：这些引文格式不一定是100％准确.
APA引文