@Article{Chickering02JMLRa,
  author =	 {David Maxwell Chickering},
  title =	 {Learning Equivalence Classes of {B}ayesian-Network
                  Structures},
  journal =	 {Journal of Machine Learning Research},
  year =	 2002,
  volume =	 2,
  pages =	 {445-498},
  month =	 {February}
}