Cita APA (7a ed.)

Drucker, P. F. (2001). The essential Drucker. Butterworth-Heinemann.

Cita Chicago Style (17a ed.)

Drucker, Peter Ferdinand. The Essential Drucker. Oxford [etc.]: Butterworth-Heinemann, 2001.

Cita MLA (9a ed.)

Drucker, Peter Ferdinand. The Essential Drucker. Butterworth-Heinemann, 2001.