H. Werthner, O. Stock, M. Zancanaro:
"Futuring Travel Destination Recommendation Systems";
in: "Destination Recommendation Systems: Behavioral Foundations and Applications", D. Fesenmaier, H. Werthner, K. Wöber (ed.); CAB International, London, 2006, ISBN: 0851990231.
http://aleph.ub.tuwien.ac.at/F?base=tuw01&func=find-c&ccl_term=AC06586835