Ee-Peng Lim Roger H. L. Chiang Yinyan Cao Tuple Source Relational Model: A Source-Aware Data Model for Multidatabases. 83-114 1999 29 Data Knowl. Eng. 1 db/journals/dke/dke29.html#LimCC99 http://dx.doi.org/10.1016/S0169-023X(99)00021-X