Katerina Raptopoulou Michael Vassilakopoulos Yannis Manolopoulos On past-time indexing of moving objects. 1079-1091 2006 79 Journal of Systems and Software 8 http://dx.doi.org/10.1016/j.jss.2005.10.020 db/journals/jss/jss79.html#RaptopoulouVM06