Crossley, John N. <br/><br/>
Combinatorial functors 
[by] J. N. Crossley [and] Anil Nerode. 
 - Berlin,  New York,  Springer-Verlag,  1974. 
 - viii, 146 p. 
<br/><br/><label>ISBN: </label>0387064281 (New York) 
<br/><br/><label>Subjects--Index Terms: </label>Combinatorics 
<br/><br/><label>Universal Decimal Class. No.: </label>519.1  / CRO