APA aipamena

Covey, S. R. (1995). Principle-centered leadership.

Chicago Style aipamena

Covey, Stephen R. Principle-centered Leadership. Simon & Schuster: London, 1995.

MLA aipamena

Covey, Stephen R. Principle-centered Leadership. 1995.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.