Covey, S. R. (2002). Principle centered leadership. Pocket books.
シカゴスタイル引用形Covey, Stephen R. Principle Centered Leadership. London.: Pocket books, 2002.
MLA引用形式Covey, Stephen R. Principle Centered Leadership. Pocket books, 2002.
警告: この引用は必ずしも正確ではありません.