Jing Liu Josh Dehlinger Hongyu Sun Robyn R. Lutz State-Based Modeling to Support the Evolution and Maintenance of Safety-Critical Software Product Lines. 596-608 2007 ECBS http://dx.doi.org/10.1109/ECBS.2007.66 conf/ecbs/2007 db/conf/ecbs/ecbs2007.html#LiuDSL07