The graphic below illustrates the process of the information retrieval cycle involving the input of published documents, e.g., books, articles, etc, and user (that's you) efforts to retrieve information from a search engine. e.g., a research literature database. The "Documents Input" box represents the input of information for published articles, books, etc. and the "User Input" box represents your efforts to identify terminology to find those articles, books, etc. that you need to find on your topic.