http://doi.acm.org/10.1145/271074.271089 Stefan Conrad Barry Eaglestone Wilhelm Hasselbring Mark Roantree Fèlix Saltor Martin Schönhoff Markus Strässler Mark W. W. Vermeer Research Issues in Federated Database Systems: Report of EFDBS '97 Workshop. 54-56 sigmodR/26-4/P054.pdf 1997 26 SIGMOD Record 4 db/journals/sigmod/sigmod26.html#ConradEHRSSSV97