A friendly introduction to number theory. 4th. Edition. 
Silverman, J. H 
 - Noida  Noida  2014 
 -  vi, 460p. 
<br/><br/><label>ISBN: </label>978-9-332-53523-7 
<br/><br/><label>Dewey Class. No.: </label>512.7 SIL