@Inproceedings{Sch-Son:VMCAI06,
  author   = {P. Schachte and H. S{\o}ndergaard},
  title    = {Closure Operators for {ROBDDs}},
  editor   = {E. A. Emerson and K. S. Namjoshi},
  booktitle= {Proceedings of the Seventh International Conference on
        	Verification, Model Checking and Abstract Interpretation},
  series   = {Lecture Notes in Computer Science},
  volume   = {3855},
  pages    = {1--16},
  publisher= {Springer},
  year     = {2006},
}