@techreport{BorndoerferNeumannPfetsch2005, author = {Ralf Bornd{\"o}rfer and Marika Neumann and Marc Pfetsch}, title = {Optimal Fares for Public Transport}, institution = {ZIB}, address = {Takustr. 7, 14195 Berlin}, number = {05-35}, language = {eng}, year = {2005} }