An intriduction to difference equations/ 
Elaydi,Saber 
 - 3rd.ed. 
 - New York:  Springer,  2005. 
 - 539 
<br/><br/><label>ISBN: </label>9788181289049 
<br/><br/><label>Dewey Class. No.: </label>515.625  / ELA/