PORTER MICHAEL E. (1998). ON COMPETITION. HARVERD BUSINESS SCHOOL.
Lua i Stíl Chicago (17ú heag.)PORTER MICHAEL E. ON COMPETITION. BOSTON: HARVERD BUSINESS SCHOOL, 1998.
Lua MLA (9ú heag.)PORTER MICHAEL E. ON COMPETITION. HARVERD BUSINESS SCHOOL, 1998.
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