एपीए उद्धरण

Drucker,Peter F. (1999). Management challenges for the 21st century. Butterworth - Heinemann.

शिकागो स्टाइल उद्धरण

Drucker,Peter F. Management Challenges for the 21st Century. Oxford: Butterworth - Heinemann, 1999.

एमएलए उद्धरण

Drucker,Peter F. Management Challenges for the 21st Century. Butterworth - Heinemann, 1999.