P. Haase, J. Broekstra, A. Eberhart, and R. Volz. The Semantic Web - ISWC 2004. Proceedings of the Third
International Semantic Web Conference, volume 3298 of Lecture Notes in Computer Science, Hiroshima, Japan, Springer-Verlag, (2004)
D. Willems, and L. Vuurpijl. Proceedings of the Ninth international conference on document analysis and recognition, page 869-873. Curitiba, Brazil, (2007)