Keene, G. B. <br/><br/>
Abstract sets and finite ordinals  an introduction to the study of set theory  
G. B. Keene 
 - New York  Dover Publications  2007 
 - vi+106p.  fig.;index.;ref. 
<br/><br/><label>ISBN: </label>9780486462493 
<br/><br/><label>Universal Decimal Class. No.: </label>510.22/.227  / KEE