@techreport{HeismannHildenbrandtSilvestrietal.2013, author = {Olga Heismann and Achim Hildenbrandt and Francesco Silvestri and Gerhard Reinelt and Ralf Bornd{\"o}rfer}, title = {HUHFA: A Framework for Facet Classification}, institution = {ZIB}, address = {Takustr. 7, 14195 Berlin}, number = {13-45}, language = {eng}, year = {2013} }