Philip K. McKinley Betty H. C. Cheng Charles Ofria David B. Knoester Benjamin E. Beckmann Heather Goldsby Harnessing Digital Evolution. 54-63 2008 41 IEEE Computer 1 http://doi.ieeecomputersociety.org/10.1109/MC.2008.17 db/journals/computer/computer41.html#McKinleyCOKBG08