@techreport{BorndoerferEisenblaetterGroetscheletal.1998, author = {Ralf Bornd{\"o}rfer and Andreas Eisenbl{\"a}tter and Martin Gr{\"o}tschel and Alexander Martin}, title = {The Orientation Model for Frequency Assignment Problems}, institution = {ZIB}, address = {Takustr. 7, 14195 Berlin}, number = {TR-98-01}, language = {eng}, year = {1998} }