Gratzer, George A. <br/><br/>
The congruences of a finite lattice :  a proof-by-picture approach / 
George Grätzer 
 - Boston ;  Basel :  Birkhäuser,  c2006 
 - xxii, 281 p. :  ill. ;  25 cm. 
<br/><br/>Includes bibliographical references (p. [265]-273) and index 
<br/><br/><label>ISBN: </label>0817632247 9780817632243 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Congruence lattices<br/>Lattice theory