@techreport{BorndoerferGroetschelLoebel2001, author = {Ralf Bornd{\"o}rfer and Martin Gr{\"o}tschel and Andreas L{\"o}bel}, title = {Duty Scheduling in Public Transit}, institution = {ZIB}, address = {Takustr. 7, 14195 Berlin}, number = {01-02}, language = {eng}, year = {2001} }