@techreport{BorndoerferGroetschelPfetsch2005, author = {Ralf Bornd{\"o}rfer and Martin Gr{\"o}tschel and Marc Pfetsch}, title = {A Column-Generation Approach to Line Planning in Public Transport}, institution = {ZIB}, address = {Takustr. 7, 14195 Berlin}, number = {05-18}, language = {eng}, year = {2005} }