Naoyasu Ubayashi Jinji Piao Suguru Shinotsuka Tetsuo Tamai Contract-Based Verification for Aspect-Oriented Refactoring. 180-189 2008 ICST http://doi.ieeecomputersociety.org/10.1109/ICST.2008.36 conf/icst/2008 db/conf/icst/icst2008.html#UbayashiPST08