Jon Bird Phil Husbands Martin Perris Bill Bigge Paul Brown Implicit Fitness Functions for Evolving a Drawing Robot. 473-478 2008 EvoWorkshops http://dx.doi.org/10.1007/978-3-540-78761-7_50 conf/evoW/2008 db/conf/evoW/evoW2008.html#BirdHPBB08