@incollection{TMCH98,
  author =	 "Bo Thiesson and Christopher Meek and David Maxwell Chickering and David Heckerman",
  title =	 "Learning Mixtures of DAG Models",
  year =	 1998,
  Booktitle =	 "Proceedings of the Fourteenth Conference on Uncertainty
                  in Artificial Intelligence, {\rm Madison,
                  Wisconsin}",
  publisher =	 "Morgan Kaufmann",
  Month =	 "August",
  editor =	 "G. Cooper and S. Moral",
  pages =        "504--513"
}