1. Born, A.: Tourismus in einer alternden Gesellschaft, Projektbericht EMPIRICA-Ges. für Kommunikations-und Technologieforschung mbH et al., Gelsenkirchen 2000
2. Carroll, J.M.: Scenario Based Design: Envisoning Work and Technology in System Development, John Wiley & Sons.Dychtwald, Ken (2000): Age Power — How the 21st century will be ruled by the new old, New York (Tarcher/Putnam/Penguin) 2000 (ISBN 0-87477-954-5)
3. Dychtwald, K.: Age Power — How the 21st century will be ruled by the new old, New York (Tarcher/Putnam/Penguin) 2000 (ISBN 0-87477-954-5)
4. Harper, S., Green, P.: An Integrating Framework for Electronic Aids to support Journeys by Visually Impaired People, in Vollmar, R., Wagner, R. (eds.): Computers Helping People with Special Needs, Proceedings of the ICCHP 2000, Karlsruhe (OCG) 2000
5. Harper, S., Green, P.: A Travel Flow and Mobility Framework for Visually impaired Travellers, in Vollmar, R., Wagner, R. (eds.): Computers Helping People with Special Needs, Proceedings of the ICCHP 2000, Karlsruhe (OCG) 2000