Willoughby, Stephen S. <br/><br/>
Real math / 
Stephen S. Willoughby. 
 - La Salle :  Open court,  c1991. 
 - 436 p. 
<br/><br/><label>ISBN: </label>081260637X 
<br/><br/><label>LC Class. No.: </label>QA 107  / .R43