Cita APA (7th ed.)

Covey, S. R. (1991). Principle-Centred Leadership. Pocket Books.

Cita Chicago (17th ed.)

Covey, Stephen R. Principle-Centred Leadership. London: Pocket Books, 1991.

Cita MLA (9th ed.)

Covey, Stephen R. Principle-Centred Leadership. Pocket Books, 1991.