APA استشهاد

Peter F.drucker. (1999). Management challenges for the 21st century. Replica press.

استشهاد بنمط شيكاغو

Peter F.drucker. Management Challenges for the 21st Century. Del;hi: Replica press, 1999.

MLA استشهاد

Peter F.drucker. Management Challenges for the 21st Century. Replica press, 1999.