@inproceedings{SAC-1993-SyangS,
	author        = "Angel Syang and Yichiang Syang",
	booktitle     = "{Proceedings of the Eighth Symposium on Applied Computing: States of the Art and Practice}",
	doi           = "10.1145/162754.165213",
	pages         = "504--510",
	publisher     = "{ACM Press}",
	title         = "{Qualitative Simulation: A Feedback Control System}",
	year          = 1993,
}