Steven Fraser Gregor Kiczales Ricardo Lopez Peter G. Neumann Linda M. Northrop Martin C. Rinard Douglas C. Schmidt Kevin Sullivan The ultra challenge: software systems beyond big. 929-933 2006 conf/oopsla/2006c OOPSLA Companion http://doi.acm.org/10.1145/1176617.1176747 db/conf/oopsla/oopsla2006c.html#FraserKLNNRSS06