A general purpose encyclopedic reference work consulted for a broad, tertiary source overview of a computing topic, rather than a specialist historical account or a primary document. Belongs here: Encyclopedia Britannica: Computer Science, Wikipedia: Hash Table, and Wikipedia: Binary Search, each a reference work summarizing established knowledge rather than a first hand or archival account. Does not belong here: a specialist historical book or journal, filed under Historical Archive, and a first hand document, filed under Primary Source Document rather than here.