T.~Heister was partially supported by the Computational Infrastructure in
Geodynamics initiative (CIG), through the National Science Foundation under Award No. EAR-0949446 and The University of California—Davis, and National Science Foundation grant DMS1522191.
-G.~Kanschat and M.~Kronbichler were partially supported by the German Research Foundation (DFG) through the project ExaDG.
+G.~Kanschat and M.~Kronbichler were partially supported by the German Research
+Foundation (DFG) through the project ExaDG. M.~Kronbichler also acknowledges
+the Gauss Centre for Supercomputing e.V.~for funding algorithm enhancements by
+providing computing time on the GCS Supercomputer SuperMUC at Leibniz
+Supercomputing Centre (LRZ) through project id \emph{pr83te}.
The Interdisciplinary Center for Scientific Computing (IWR) at Heidelberg University has provided
hosting services for the \dealii{} web page and the SVN archive.