B. Martins, H. Manguinhas, и J. Borbinha. Proceedings of the International Conference on Semantic Computing, стр. 1--9. IEEE Computer Society, (августа 2008)
G. Gottlob, C. Koch, R. Baumgartner, M. Herzog, и S. Flesca. Proceedings of the Twenty-third ACM SIGACT-SIGMOD-SIGART Symposium
on Principles of Database Systems, June 14-16, 2004, Paris, France, стр. 1-12. ACM, (2004)