: A_semantic_web_middleware_for_virtual_data_integration_on_the_webhttp://purl.org/semsur/ Create a prefix for http://purl.org/semsur/ Hit Enter to save Double click to create a prefix | : subjecthttp://purl.org/SemSur/ Create a prefix for http://purl.org/SemSur/ Hit Enter to save Double click to create a prefix | Querying Distributed RDF Data Sources | : SemSur/http://purl.org/ Create a prefix for http://purl.org/ Hit Enter to save Double click to create a prefix |