@article{TUW-166268, author = {Frank, Andrew U.}, title = {Shortest Path in a Multi-Modal Transportation Network}, journal = {KI K{\"u}nstliche Intelligenz}, year = {2008}, volume = {3}, number = {3}, pages = {14--18}, url = {http://publik.tuwien.ac.at/files/PubDat_166268.pdf} }