Steven M. Gustafson Edmund K. Burke Natalio Krasnogor The Tree-String Problem: An Artificial Domain for Structure and Content Search. 215-226 http://dx.doi.org/10.1007/978-3-540-31989-4_19 2005 conf/eurogp/2005 EuroGP db/conf/eurogp/eurogp2005.html#GustafsonBK05