Andrew Tokmakoff François-Xavier Nuttall Kyunghee Ji MPEG-21 Event Reporting: Enabling Multimedia E-Commerce. 50-59 2005 12 IEEE MultiMedia 4 http://doi.ieeecomputersociety.org/10.1109/MMUL.2005.77 db/journals/ieeemm/ieeemm12.html#TokmakoffNJ05