@conference {16747, title = {MOCHA: a self-extensible database middleware system for distributed data sources}, booktitle = {ACM SIGMOD Record}, volume = {29}, year = {2000}, month = {2000///}, pages = {213 - 224}, author = {Rodr{\'\i}guez-Mart{\'\i}nez,M. and Roussopoulos, Nick} }