Nathan R. Sturtevant Ariel Felner Max Barrer Jonathan Schaeffer Neil Burch Memory-Based Heuristics for Explicit State Spaces. 609-614 2009 IJCAI http://ijcai.org/papers09/Papers/IJCAI07-107.pdf conf/ijcai/2009 db/conf/ijcai/ijcai2009.html#SturtevantFBSB09