Ramana Rao Stuart K. Card Herbert D. Jellinek Jock D. Mackinlay George G. Robertson The Information Grid: A Framework for Information Retrieval and Retrieval-centered Applications. 23-32 1992 ACM Symposium on User Interface Software and Technology http://doi.acm.org/10.1145/142621.142625 db/conf/uist/uist1992.html#RaoCJMR92