http://doi.acm.org/10.1145/381854.381893 db/journals/sigmod/FreemanG96.html Eric Freeman David Gelernter Lifestreams: A Storage Model for Personal Data. 80-86 sigmodR/25-1/P080.pdf 1996 25 SIGMOD Record 1 db/journals/sigmod/sigmod25.html#FreemanG96 http://www.acm.org/sigmod/record/issues/9603/lifestreams.ps