@article{ICLP-J-2012-LifschitzPY,
	author        = "Vladimir Lifschitz and Karl Pichotta and Fangkai Yang",
	doi           = "10.1017/S147106841200018X",
	journal       = "{Theory and Practice of Logic Programming}",
	number        = "4-5",
	pages         = "565--582",
	title         = "{Relational theories with null values and non-herbrand stable models}",
	volume        = 12,
	year          = 2012,
}