Ulrich Meyer Vitaly Osipov Design and Implementation of a Practical I/O-efficient Shortest Paths Algorithm. 85-96 2009 ALENEX http://www.siam.org/proceedings/alenex/2009/alx09_009_meyeru.pdf conf/alenex/2009 db/conf/alenex/alenex2009.html#MeyerO09