@Article{	  Bungartz.Griebel.Roschke.ea:1996,
  author	= {H.-J. Bungartz and M. Griebel and D. R\"oschke and C.
		  Zenger},
  title		= {A proof of convergence for the combination technique for
		  the {L}aplace equation using tools of symbolic
		  computation},
  journal	= {Math. Comp. in Simulation},
  volume	= {42},
  year		= {1996},
  note		= {also in G.~Jacob, N.~Oussous and S.~Steinberg, Editoren, {
		  IMACS Symposium on Symbolic Computation, Lille, Juni 1993}.
		  IMACS/Universite des Sciences et Technologies de Lille,
		  Villeneuve d'Ascq, 1993 and as SFB Bericht, 342/4/93 A,
		  Institut f\"ur Informatik, TU M\"unchen, 1993},
  annote	= {article},
  pages		= {595--605}
}