Young Francis Day Ashfaq A. Khokhar Serhan Dagtas Arif Ghafoor A Multi-Level Abstraction and Modeling in Video Databases. 409-423 1999 7 Multimedia Syst. 5 http://link.springer.de/link/service/journals/00530/bibs/9007005/90070409.htm db/journals/mms/mms7.html#DayKDG99