Stephen R. Covey, A. Roger Merrill, Rebecca R. Merrill (1997). “First Things First Every Day: Daily Reflections- Because Where You're Headed Is More Important Than How Fast You Get There”, p.115, Simon and Schuster
Stephen R. Covey, A. Roger Merrill, Rebecca R. Merrill (1997). “First Things First Every Day: Daily Reflections- Because Where You're Headed Is More Important Than How Fast You Get There”, p.115, Simon and Schuster