KOONTZ, H., O'DONNELL, C., & WEIHRICH, H. (1986). Essentials of management.-- ed. 4. McGraw-Hill.

KOONTZ, Harold, Cyril O'DONNELL, and Heinz WEIHRICH. Essentials of Management.-- Ed. 4. New York: McGraw-Hill, 1986.

KOONTZ, Harold, et al. Essentials of Management.-- Ed. 4. McGraw-Hill, 1986.