Porter, M. E. (1998). Competitive Strategy. Free Press.
Chicago-čujuhus (17. p.)Porter, Michael E. Competitive Strategy. New York: Free Press, 1998.
MLA-čujuhus (9. p.)Porter, Michael E. Competitive Strategy. Free Press, 1998.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.