Lucas Bordeaux Marco Cadoli Toni Mancini A Unifying Framework for Structural Properties of CSPs: Definitions, Complexity, Tractability. 607-629 2008 32 J. Artif. Intell. Res. (JAIR) http://jair.org/papers/paper2538.html db/journals/jair/jair32.html#BordeauxCM08