Engel, Konrad. <br/><br/>
Sperner Theory   
by Konrad Engel 
 - Cambridge  Cambridge Univ.Press  1997 
 - ix, 417p. 
 - Encyclopedia of mathematics and its applications  V.65 .
<br/><br/><label>ISBN: </label>0521452066 
<br/><br/><label>Dewey Class. No.: </label>511.32  / N97