@techreport{ilprints503,
          number = {2001-33},
          author = {Brian Babcock and Mayur Datar and Rajeev Motwani},
           title = {Sampling From a Moving Window Over Streaming Data},
            type = {Technical Report},
       publisher = {Stanford InfoLab},
     institution = {Stanford InfoLab},
         journal = {2002 Annual ACM-SIAM Symposium on Discrete Algorithms (SODA 2002)},
            year = {2001},
             url = {http://ilpubs.stanford.edu:8090/503/},
        abstract = {We consider the problem of maintaining statistics over sliding windows. We design data structures with small memory requirements and provide matching lower bounds.}
}