1. AltaVista. (2002). Description of Prisma query refinement feature.
2. Retrieved January 15, 2003, from http://www.altavista.com/help/search/pp
3. & (1999). The paraphrase search assistant: Terminological feedback for iterative information seeking. In , & (Eds.), Proceedings of the 22nd Annual International Conference on Research and Development in Information Retrieval (SIGIR '99; pp. 153–159). New York: ACM.
4. (1991). The berrypicking search: User interface design. In (Ed.), Interfaces for information retrieval. Westport, CT: Greenwood Press.