@inproceedings{DLT-1997-Kuich,
	author        = "Werner Kuich",
	booktitle     = "{Proceedings of the Third International Conference on Developments in Language Theory}",
	pages         = "49--60",
	publisher     = "{Aristotle University of Thessaloniki}",
	title         = "{Semirings: A basis for a mathematical automata and language theory}",
	year          = 1997,
}