Cristian Morariu, Reto Zimmermann, Burkhard Stiller: Implementation of a Non-Repudiation Approach for Web-Services in Mobile Grids; "12th Eunice Summer School 2006", Binzmuehlestrasse 14, 8050, ZH, September 2006, URL: http://www.csg.uzh.ch/staff/morariu/publications/Eunice2006.ppt.