1. Maryam Hourali and Gholam Ali Montazer, “An Intelligent Information Retrieval Approach Based on Two Degrees of Uncertainty Fuzzy Ontology”, Hindawi Publishing Corporation Advances in Fuzzy Systems Volume 2011.
2. Gibbons, Kevin. “Do, Know, Go: How to Create Content at Each Stage of the Buying Cycle”. Search Engine Watch. Retrieved 24 May 2014.
3. Gyöngyi, Zoltán; Berkhin, Pavel; Garcia-Molina, Hector; Pedersen, Jan (2006), “Link spam detection based on mass estimation”, Proceedings of the 32nd International Conference on Very Large Data Bases (VLDB ‘06, Seoul, Korea), pp. 439-450.
4. Page, Larry, “PageRank: Bringing Order to the Web” at the Wayback Machine (archived May 6, 2002), Stanford Digital Library Project, talk. August 18, 1997 (archived 2002).
5. Fields, Kenneth (2007) “Ontologies, categories, folksonomies: an organised language of sound.” Cambridge.M. Young, The Technical Writer's Handbook. Mill Valley, CA: University Science, 1989.