Learning Classifier Systems: 10th International Workshop, IWLCS 2006, Seattle, MA, USA, July 8, 2006, and 11th International Workshop, IWLCS 2007, London, UK, July 8, 2007, Revised Selected Papers by Jaume Bacardit, Tim Kovacs, Keiki Takadama, Martin V. Butz, Xavier Llora, Ester Bernado-Mansilla (Paperback, 2008)