@inproceedings{ICALP-1998-Walukiewicz,
	author        = "Igor Walukiewicz",
	booktitle     = "{Proceedings of the 25th International Colloquium on Automata, Languages and Programming}",
	doi           = "10.1007/BFb0055048",
	isbn          = "3-540-64781-3",
	pages         = "140--151",
	publisher     = "{Springer-Verlag}",
	series        = "{Lecture Notes in Computer Science}",
	title         = "{Difficult Configurations — On the Complexity of LTrL}",
	volume        = 1443,
	year          = 1998,
}