Schaaf, William Leonard. <br/><br/>
Basic concepts of elementary mathematics / 
[by] William L. Schaaf. 
 - 3rd ed. 
 - New York :  Wiley,  1969. 
 - xx, 500 p. :  ill. 
<br/><br/><label>ISBN: </label>0471756717 
<br/><br/><label>LCCN: </label>93034233     
<br/><br/><label>Subjects--Topical Terms: </label><br/>Mathematics.