10. A computer system, comprising: one or more processors; and a memory storage storing one or more instructions for implementing a search tool, wherein the instructions, when executed, instruct the computer system to perform: generating a database, the database storing information on one or more sources; for each of the one or more sources: extracting one or more keywords from a set of documents associated with the source, based on the extracted keywords, determining a set of one or more keywords, and storing the set of one or more keywords in the database in association with the source receiving a search query from a user computer, the search query including one or more search terms; and determining a set of documents responsive to the search query; determining a set of citations cited in the set of documents by extracting data having recognized citation formats from the set of documents; providing for display at the user computer a list of the set of citations that enables determination of the most frequent citation by a user viewing the displayed list; and based on the one or more search terms, and the one or more keywords stored in the database, providing for display at the user computer a set of one or more recommended sources from the one or more sources in which to search for documents.
18. The computer system of claim 10 , wherein the memory storage stores one or more instructions that, when executed, further instruct the computer system to perform: receiving a selection of one of the citations; and in response to the selection, providing for display a list of a subset of documents, the subset of documents including documents from the set of documents that include the selected citation.