Nicolas Meuleau Ronen I. Brafman Hierarchical Heuristic Forward Search in Stochastic Domains. 2542-2549 2007 conf/ijcai/2007 IJCAI http://dli.iiit.ac.in/ijcai/IJCAI-2007/PDF/IJCAI07-409.pdf db/conf/ijcai/ijcai2007.html#MeuleauB07