Manfred Broy Christian Leuxner Wassiou Sitou Bernd Spanfelner Sebastian Winter Formalizing the notion of adaptive system behavior. 1029-1033 2009 SAC http://doi.acm.org/10.1145/1529282.1529508 conf/sac/2009 db/conf/sac/sac2009.html#BroyLSSW09