Peter Drucker, Alan Kantrow, Rick Wartzman, Julia Kirby (2016). “Get the Right Things Done: The Drucker Collection (6 Items)”, p.33, Harvard Business Review Press
Peter Drucker, Harvard Business Review (2016). “The Peter F. Drucker Reader: Selected Articles from the Father of Modern Management Thinking”, p.9, Harvard Business Review Press
Peter Drucker, Alan Kantrow, Rick Wartzman, Julia Kirby (2016). “Get the Right Things Done: The Drucker Collection (6 Items)”, p.33, Harvard Business Review Press
Peter Drucker, Harvard Business Review (2016). “The Peter F. Drucker Reader: Selected Articles from the Father of Modern Management Thinking”, p.59, Harvard Business Review Press
Peter Drucker, Harvard Business Review (2016). “The Peter F. Drucker Reader: Selected Articles from the Father of Modern Management Thinking”, p.49, Harvard Business Review Press
Peter Drucker, Harvard Business Review (2016). “The Peter F. Drucker Reader: Selected Articles from the Father of Modern Management Thinking”, p.8, Harvard Business Review Press