Ioannis Refanidis Ioannis P. Vlahavas The GRT Planning System: Backward Heuristic Construction in Forward State-Space Planning. 115-161 2001 15 J. Artif. Intell. Res. (JAIR) http://www.cs.washington.edu/research/jair/abstracts/refanidis01a.html db/journals/jair/jair15.html#RefanidisV01