François-Fabien Ferhani Nirmal R. Saxena Edward J. McCluskey Phil Nigh How Many Test Patterns are Useless? 23-28 2008 VTS http://doi.ieeecomputersociety.org/10.1109/VTS.2008.27 conf/vts/2008 db/conf/vts/vts2008.html#FerhaniSMN08