Chi-Wai Fung Elvis Wai Chung Leung Qing Li Efficient Query Execution Techniques in a 4DIS Video Database System for eLearning. 25-49 2003 20 Multimedia Tools Appl. 1 http://dx.doi.org/10.1023/A:1023418316038 db/journals/mta/mta20.html#FungLL03