Wallis, W. D. <br/><br/>
Introduction to combinatorics  / 

 - Boca Raton:  CRC Press,  2011 
 - xvi, 380p. Bibl. Index. 
 - Discrete Mathematics and its applications .
<br/><br/><label>ISBN: </label>9781439806227 
<br/><br/><label>Dewey Class. No.: </label>511.6  / W214.IC