APA (7th ed.) Citation

DRUCKER. (1999). Management challenges for the 21st century. HarperCollins Pubs.

Chicago Style (17th ed.) Citation

DRUCKER. Management Challenges for the 21st Century. New York: HarperCollins Pubs, 1999.

MLA (9th ed.) Citation

DRUCKER. Management Challenges for the 21st Century. HarperCollins Pubs, 1999.

Warning: These citations may not always be 100% accurate.