Cita APA (7th ed.)
Drucker, P. F. The effective executive. Pan books.
Cita Chicago (17th ed.)
Drucker, Peter F. The Effective Executive. London: Pan books.
Cita MLA (9th ed.)
Drucker, Peter F. The Effective Executive. Pan books.
Atenció: Aquestes cites poden no estar 100% correctes.