1. Searching the Web
2. Balancing Volume, Quality and Freshness in Web Crawling;R.Baeza-Yates;Soft-Computing Systems: Design, Management and Applications, Frontiers in Artificial Intelligence and Applications 97,2002
3. Understanding Information Retrieval Systems
4. Retrieval System Evaluation;C.Buckley;TREC: Experiment and Evaluation in Information Retrieval,2005