Mei Si, David Thue, Elisabeth André, James C. Lester, Theresa Jean Tanenbaum, Veronica Zammitto: Interactive Storytelling - Fourth International Conference on Interactive Digital Storytelling, ICIDS 2011, Vancouver, Canada, November 28 - 1 December, 2011. Proceedings. Lecture Notes in Computer Science 7069, Springer 2011, ISBN 978-3-642-25288-4