APA (7th ed.) Zitazioa
Hybels, B. (2009). Courageous leadership (Expanded edition.). Zondervan.
Chicago Style (17th ed.) Zitazioa
Hybels, Bill. Courageous Leadership. Expanded edition. Grand Rapids, Mich.: Zondervan, 2009.
MLA (9th ed.) Zitazioa
Hybels, Bill. Courageous Leadership. Expanded edition. Zondervan, 2009.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.