Enrique Castillo Juan M. Fernández-Luna Pilar Sanmartin Marginalizing in Undirected Graph and Hypergraph Models. 69-78 1998 conf/uai/1998 UAI http://rome.exp.sis.pitt.edu/UAI/Abstract.asp?articleID=234&proceedingID=14 db/conf/uai/uai1998.html#CastilloFS98