A. Tjoa, H. Werthner:
"E-commerce and Tourism: Retrospectives and Perspectives";
in: "The Digital Economy - Anspruch und Wirklichkeit", K. Stanoevska-Slabeva (ed.); Springer, Berlin Heidelberg, 2004, ISBN: 3-540-20850-x, 165 - 180.
http://aleph.ub.tuwien.ac.at/F?base=tuw01&func=find-c&ccl_term=AC04968611