Godin, S. (2002). Purple Cow: Transform your Questions (NA.). Penguin Books.
Chicago-čujuhus (17. p.)Godin, Seth. Purple Cow: Transform Your Questions. NA. England: Penguin Books, 2002.
MLA-čujuhus (9. p.)Godin, Seth. Purple Cow: Transform Your Questions. NA. Penguin Books, 2002.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.