Jörg Westbomke, Uffe Kock Wiil, John J. Leggett, Klaus Tochtermann, Jörg M. Haake: HYPERTEXT '99, Proceedings of the 10th ACM Conference on Hypertext and Hypermedia: Returning to Our Diverse Roots, February 21-25, 1999, Darmstadt, Germany. ACM 1999