Drucker, P. F. (2001). The essential Drucker: The best of sixty years of Peter Drucker's essential writings on management. New York: Collins Business Essentials.
Dyfyniad Arddull ChicagoDrucker, Peter F. The Essential Drucker: The Best of Sixty Years of Peter Drucker's Essential Writings On Management. New York: Collins Business Essentials, 2001.
Dyfyniad MLADrucker, Peter F. The Essential Drucker: The Best of Sixty Years of Peter Drucker's Essential Writings On Management. New York: Collins Business Essentials, 2001.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.