Sebastian Knopp Peter Sanders Dominik Schultes Frank Schulz Dorothea Wagner Computing Many-to-Many Shortest Paths Using Highway Hierarchies. 2007 conf/alenex/2007 ALENEX http://www.siam.org/proceedings/alenex/2007/alx07_004knopps.pdf db/conf/alenex/alenex2007.html#KnoppSSSW07