Covey, S. (1992). The seven habits of highly effective people. Simon & Schuster.
Chicagoスタイル(17版)引用形式Covey, Stephen. The Seven Habits of Highly Effective People. London: Simon & Schuster, 1992.
MLA(9版)引用形式Covey, Stephen. The Seven Habits of Highly Effective People. Simon & Schuster, 1992.
警告: この引用は必ずしも正確ではありません.