Information Retrieval.
C. J. van Rijsbergen.
http://www.dcs.gla.ac.uk/Keith/Preface.html

Managing Gigabytes.
Ian H. Witten and Alistair Moffat and Timothy C. Bell .
Van Nostrand Reinhold. 1994.

Readings in Information Retrieval.
Karen Sparck-Jones and Peter Willet. Morgan Kaufmann. 1997.

Information Retrieval, Data Structures & Algorithms.
Ricardo Baeza-Yates. Prentice Hall. 1992.

Modern Information Retrieval.
Ricardo Baeza-Yates and Berthier Ribeiro-Neto.
Addison-Wesley. 1999.
http://www.amazon.com/exec/obidos/ASIN/020139829X/corazone

Information Retrieval.
http://www.wkap.nl/journalhome.htm/1386-4564

ACM Transactions on Information Systems.
http://www.acm.org/tois/

Information Processing and Management.
http://www.elsevier.nl/inca/publications/store/2/4/4/

SIGIR Conference.
http://www.sigir.org/

Digital Libraries Conference.
http://www.jcdl.org/

WWW Conferences.
http://www.iw3c2.org/

Information Retrieval is the process of locating information that fits a user's information need, which is usually expressed as a search query. The fit of the retrieved information with the information need is referred to as "relevance". The information can be retrieved from databases (data retrieval) or from document collections (document retrieval), where documents can either be text documents or other media (audio, video, semi-structured data, multimedia). Success in information retrieval is generally defined by retrieving as much relevant information as possible (measured by "recall") while minimising the irrelevant information retrieved (measured by "precision"). The most widely used information retrieval systems today are Internet search engines.