Ary, Donald <br/><br/>
Introduction to research in education/ 
Donald Ary 
 - 6th ed. 
 - Singapore :   Wadsworth/Thomson Learning,   c2002. 
 - xxi, 582 p. ;   23 cm. 
<br/><br/> Includes index. 
<br/><br/><label>ISBN: </label>0-534-24665-6 
<br/><br/><label>Dewey Class. No.: </label>Circ. 370.72 Am96i 2002