Leedy, Paul D. <br/><br/>
Practical research :  planning and design / 
Paul D. Leedy, Jeanne Ellis Ormrod 
 - 6 
 - New Jersey :  Merrill Prentice Hall,  1985       
 - xx, 318 p. 
<br/><br/><label>ISBN: </label>0139603603 
<br/><br/><label>LC Class. No.: </label>Q 180 L484p 2001