@inproceedings{SAT-2011-KullmannZ,
	author        = "Oliver Kullmann and Xishun Zhao",
	booktitle     = "{Proceedings of the 14th International Conference on Theory and Applications of Satisfiability Testing}",
	doi           = "10.1007/978-3-642-21581-0_5",
	isbn          = "978-3-642-21580-3",
	pages         = "33--46",
	publisher     = "{Springer International Publishing}",
	series        = "{Lecture Notes in Computer Science}",
	title         = "{On Variables with Few Occurrences in Conjunctive Normal Forms}",
	volume        = 6695,
	year          = 2011,
}