Wallis, Walter D. and George, John C. <br/><br/>
Introduction to combinatorics  / 

 - 2nd 
 - Boca Raton:  CRC Press,  2017 
 - xix, 423p. Bibl. Index 
 - Discrete Mathematics and Its Applications .
<br/><br/><label>ISBN: </label>9781498777605 
<br/><br/><label>Dewey Class. No.: </label>511.6  / W214.IC