P. Hannappel, R. Klapsing, A. Krug, and G. Neumann. Managing Information Technology Resources in Organizations in the Next Millennium: Proceedings of the 10th Information Resources Management Association International Conference, Idea Group Publishing, (1999)
S. Chakrabarti, M. Joshi, and V. Tawde. Proceedings of the 24th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, page 208-216. ACM Press, (2001)
B. Davison. Proceedings of the 26th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, page 367-368. ACM Press, (2003)