Covey, Stephen R. <br/><br/>
Principle-centered leadership 
/ Stephen R. Covey 
. - New-York  : Summit Books, 1991
. - 334 p.  : ill.  ; 24 cm. 
<br/><br/>Index 
<br/><br/><label>ISBN: </label>9780671749101 
<br/><br/><label>Source: </label> Don 
<br/><br/><label>Universal Decimal Class. No.: </label>159.922.