KOONTZ, Harold; WEIHRICH, Heinz. Essentials of management. Fifth edition.
McGraw-Hill, 1990. 529 p. ISBN 0-07-100776.
DRUCKER, Peter F. The essential Drucker. In One Volume the Best of Sixty Years of Peter Drucker's Essential Writings on Management. New York : Harper Collins Publishers Inc., 2001. 368 p. ISBN: 006093574X .