(1961) "Observations on the Span of Control", "Administrative Sciences Quarterly", 1961* Drucker, Peter (1954), "The Practice of Management", Harper, New York* Gulick, L. and Urwick, L. (1937) (eds), "Papers on the Science of Administration", Institute of Public Administration, New York* Koontz, H. (1966) "Making Theory Operational: The Span of Management", "The Journal of Management Studies", Vol 3, 1966.
(1961) "Observations on the Span of Control", "Administrative Sciences Quarterly", 1961* Drucker, Peter (1954), "The Practice of Management", Harper, New York* Gulick, L. and Urwick, L. (1937) (eds), "Papers on the Science of Administration", Institute of Public Administration, New York* Koontz, H. (1966) "Making Theory Operational: The Span of Management", "The Journal of Management Studies", Vol 3, 1966.