CEI. (1991). PROFIT THROUGH QUALITY. C E I.
Chicago-čujuhus (17. p.)CEI. PROFIT THROUGH QUALITY. C E I, 1991.
MLA-čujuhus (9. p.)CEI. PROFIT THROUGH QUALITY. C E I, 1991.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.