Klaus Fischer Dieter Hutter Matthias Klusch Werner Stephan Towards Secure Mobile Multiagent Based Electronic Marketplace Systems. 2001 63 Electr. Notes Theor. Comput. Sci. http://www.elsevier.com/gej-ng/31/29/23/118/25/show/Products/notes/index.htt#006 db/journals/entcs/entcs63.html#FischerHKS01