Sharp, I. (2012). Four Seasons: The story of a business philosophy. Portfolio/Penguin.
Chicago-čujuhus (17. p.)Sharp, Isadore. Four Seasons: The Story of a Business Philosophy. New York: Portfolio/Penguin, 2012.
MLA-čujuhus (9. p.)Sharp, Isadore. Four Seasons: The Story of a Business Philosophy. Portfolio/Penguin, 2012.
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