Ries, A. (1996). Focus: The feature of your company depends on it. Harper Collins Publishers.
Čikaški stil citiranjaRies, AI. Focus: The Feature of Your Company Depends on It. New York: Harper Collins Publishers, 1996.
MLA način citiranjaRies, AI. Focus: The Feature of Your Company Depends on It. Harper Collins Publishers, 1996.
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