Kortenkamp, U. H., & Richter-Gebert J.  (1998).  Geometry and education in the Internet age.  (Ottmann, T., & Tomek I., Ed.).Ed-Media & Ed-Telecom 98. Proceedings of the Tenth World Conference on Educational Multimedia and Hypermedia & World Conference on Educational Telecommunications, Freiburg, Germany, June 20-25, 1998.