Library information services refers to the various ways in which a library provides access to information and resources to its patrons. Some synonyms for library information services include reference services, research assistance, information retrieval, information access, document delivery, and knowledge management. Reference services involve answering questions and providing guidance on using library resources. Research assistance is more in-depth support for conducting research, such as help with searching databases and locating appropriate sources. Information retrieval and access refer to methods of obtaining materials from the library, including interlibrary loan and digital lending. Document delivery focuses on obtaining materials not held by the library. Knowledge management is a broader concept, encompassing the organization, sharing, and dissemination of knowledge and information.