@inproceedings{VLDB-1992-LiuM,
	author        = "Ling Liu and Robert Meersman",
	booktitle     = "{Proceedings of the 18th International Conference on Very Large Data Bases}",
	ee            = "http://www.vldb.org/conf/1992/P481.PDF",
	isbn          = "1-55860-151-1",
	pages         = "481--493",
	publisher     = "{Morgan Kaufmann}",
	title         = "{Activity Model: A Declarative Approach for Capturing Communication Behavior in Object-Oriented Databases}",
	year          = 1992,
}