Porter, M. E. (1998). On competition. Harvard Businesss School Publishing.
Chicago-čujuhus (17. p.)Porter, Michael E. On Competition. Boston: Harvard Businesss School Publishing, 1998.
MLA-čujuhus (9. p.)Porter, Michael E. On Competition. Harvard Businesss School Publishing, 1998.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.