104 number theory problems : 
Andreescu, Titu, 
 - Boston :  Birkhäuser,  2007 
 - xii, 204 p. :  ill. ;  24 cm. 
<br/><br/><label>ISBN: </label>9780817645274 (acid-free paper) | 0817645276 (acid-free paper) | 9780817645618 (e-ISBN) | 0817645616 (e-ISBN)