Godin, S. (2002). Purple Cow: Transform your Questions (NA.). Penguin Books.
Chicagoスタイル(17版)引用形式Godin, Seth. Purple Cow: Transform Your Questions. NA. England: Penguin Books, 2002.
MLA(9版)引用形式Godin, Seth. Purple Cow: Transform Your Questions. NA. Penguin Books, 2002.
警告: この引用は必ずしも正確ではありません.