.Drucker, P. F. (2000). Management challenges for the 21st century. Butterworth-Heinemann.
Cita Chicago Style (17a ed.).Drucker, Peter F. Management Challenges for the 21st Century. Oxford: Butterworth-Heinemann, 2000.
Cita MLA (9a ed.).Drucker, Peter F. Management Challenges for the 21st Century. Butterworth-Heinemann, 2000.