@InCollection{Beckert98,
  author	= {Bernhard Beckert},
  title		= {Rigid {$E$}-Unification},
  part  	= {2: Special Calculi and Refinements},
  volume        = {{I}: Foundations},
  pages         = {265--289},		  
  booktitle	= {Automated Deduction --- A Basis for Applications},
  editor	= {Wolfgang Bibel and Peter H. Schmitt},
  publisher	= {Kluwer, Dordrecht},
  year		= {1998}
}