Hernandez, C., P. Meseguer, X. Sun, and S. Koenig. “Path-Adaptive A* for Incremental Heuristic Search in Unknown Terrain”. Proceedings of the International Conference on Automated Planning and Scheduling, vol. 19, no. 1, Oct. 2009, pp. 358-61, doi:10.1609/icaps.v19i1.13395.