A pre-relational databases datamodel. "Preceeded" by the relational model since the flexibility of this makes it hard to work with. Now re-invented in RDF :)
K. Bade, and D. Benz. Proceedings of the 32nd Annual Conference of the German Classification Society - Advances in Data Analysis, Data Handling and Business Intelligence (GfKl 2008), Berlin-Heidelberg, Springer, (2008)in press.
S. Baluja, D. Ravichandran, and D. Sivakumar. Proceeding of the International Conference on Knowledge Discovery and Information Retrieval (KDIR 2009), INSTICC, (6-8 10 2009)
M. Banko, and E. Brill. ACL '01: Proceedings of the 39th Annual Meeting on Association for Computational Linguistics, page 26--33. Morristown, NJ, USA, Association for Computational Linguistics, (2001)
B. Berendt, A. Hotho, and G. Stumme. International Semantic Web Conference, volume 2342 of Lecture Notes in Computer Science, page 264 - 278. Springer Verlag, (2002)