COVEY S. R., . (1989). SEVEN HABITS OF HIGHLY EFFECTIVE PEOPLE. : SIMON & SCHUSTER,NEW YORK.
COVEY STEPHEN R, . 1989. SEVEN HABITS OF HIGHLY EFFECTIVE PEOPLE. : SIMON & SCHUSTER,NEW YORK.
COVEY STEPHEN R, . SEVEN HABITS OF HIGHLY EFFECTIVE PEOPLE. : SIMON & SCHUSTER,NEW YORK. 1989.
