APA aipamena

Covey, S. R. (1991). Principle centered leadership. New York: A Fireside.

Chicago Style aipamena

Covey, Stephen R. Principle Centered Leadership. New York: A Fireside, 1991.

MLA aipamena

Covey, Stephen R. Principle Centered Leadership. New York: A Fireside, 1991.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.