Barbara Hammer Alessio Micheli Alessandro Sperduti A general framework for unsupervised preocessing of structured data. 2007 Probabilistic, Logical and Relational Learning - A Further Synthesis http://drops.dagstuhl.de/opus/volltexte/2008/1383 conf/dagstuhl/2007P7161 db/conf/dagstuhl/P7161.html#HammerMS07