Gaya APA

Drucker, P, F. (2001). The essential drucker: the best of sixty years of Peter Drucker's essential writings on management . New York: HarperCollins.

Gaya MLA

Drucker, Peter, F.. "The essential drucker: the best of sixty years of Peter Drucker's essential writings on management". New York: HarperCollins, 2001. Text.