Sewell, C. (2002). Customers for Life (1st.). Crown Business.
Chicago-čujuhus (17. p.)Sewell, Carl. Customers for Life. 1st. Crown Business, 2002.
MLA-čujuhus (9. p.)Sewell, Carl. Customers for Life. 1st. Crown Business, 2002.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.