Mehrdad Sabetzadeh Steve M. Easterbrook Analysis of Inconsistency in Graph-Based Viewpoints: A Category-Theoretic Approach. 12-21 2003 conf/kbse/2003 ASE http://doi.ieeecomputersociety.org/10.1109/ASE.2003.1240290 db/conf/kbse/ase2003.html#SabetzadehE03