Neil T. Heffernan Peter M. Wiemer-Hastings Gregory Aist Vincent Aleven Ivon Arroyo Paul Brna Mark G. Core Martha W. Evens Reva Freedman Michael Glass Arthur C. Graesser Kenneth R. Koedinger Pamela W. Jordan Diane J. Litman Evelyn Lulis Helen Pain Carolyn Penstein Rosé Beverly Park Woolf Claus Zinn Workshop on Dialog-Based Intelligent Tutoring Systems: State of the Art and New Research Directions. 914 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3220&spage=914 2004 conf/its/2004 Intelligent Tutoring Systems db/conf/its/its2004.html#HeffernanWAAABCEFGGKJLLPRWZ04