1. Cyveillance: http://www.cyveillance.com/.
2. Hypertext information retrieval for the web;Brown;ACM SIGIR Forum,1998
3. Context in web search;Lawrence;IEEE Data Eng. Bull.,2000
4. Accessibility of information on the web;Lawrence;Nature J.,1999
5. M. Diligenti, F.M. Coetzee, S. Lawrence, C.L. Giles, Focused crawling using context graphs, The 26th International Conference on Very Large Database (VLDB), 2000, pp. 527–534.