@InCollection{	  BeckertHandbook99,
  author        = {Bernhard Beckert},		  
  title         = {Equality and Other Theories}, 		  
  booktitle	= {Handbook of Tableau Methods},
  editor	= {M. D'Agostino and D. Gabbay and R. H\"ahnle and
		  J. Posegga},
  publisher	= {Kluwer, Dordrecht},
  year		= {1999}
}