Göbelbecker, M., Keller, T., Eyerich, P., Brenner, M., & Nebel, B. (2010). Coming Up With Good Excuses: What to do When no Plan Can be Found. Proceedings of the International Conference on Automated Planning and Scheduling, 20(1), 81–88. https://doi.org/10.1609/icaps.v20i1.13421