1. J. Allen. Maintaining Knowledge About Temporal Intervals. Comm. ACM, Vol. 26, No. 11, 1983.
2. R. Belew. Finding Out About: A Cognitive Perspective on Search Technology and the WWW. Cambridge University Press, Cambridge, U.K., 2000.
3. D. Barreau. Context as a Factor in Personal Information Management Systems. J. Am. Soc. For Information Science, Vol. 46, No. 5:327–339, 1995.
4. “Log your Life Via Your Phone”, March 10, 2004, http://news.bbc.co.uk/2/hi/technology/
5. BBN Technologies. OpenMap-Open Systems Mapping Technology, 1999