1. Batra, M.R.: A review of focused crawler approaches. Int. J. 4(7), (2014)
2. Pant, G., Srinivasan, P.: Link contexts in classifier-guided topical crawlers. IEEE Trans. Knowl. Data Eng. 18(1), 107–122 (2006)
3. www.wikipedia.org/web_crawler
. Accessed 12 May 2010
4. Pal, A., Tomar, D.S., Shrivastava, S.C.: Effective focused crawling based on content and link structure analysis. 2(1), (2009)
5. De Bra, P., Houben, G.-J., Kornatzky, Y., Post, R.: Information retrieval in distributed hypertexts. In: Proceedings of RIAO-94, Intelligent Multimedia, Information Retrieval Systems and Management, pp. 481–492 (1994)