Godin, S. (2002). Purple Cow: Transform your Questions (NA.). Penguin Books.
芝加哥风格引文Godin, Seth. Purple Cow: Transform Your Questions. NA. England: Penguin Books, 2002.
MLA引文Godin, Seth. Purple Cow: Transform Your Questions. NA. Penguin Books, 2002.
警告：这些引文格式不一定是100％准确.