Goldberg statistical machine patent, 29 December 1931. This is part of the application filed with the US Patent Office on 5 April 1928 by Russian-Israeli physicist and inventor Emanuel Goldberg (1881-1970) for a design for a statistical machine. This is considered the first functioning electronic document retrieval system. Developed at Zeiss Ikon in Germany, it was designed to retrieve documents that had been microfilmed. It laid the groundwork for early 'selector' and 'comparator' electronic systems developed at MIT by Vannevar Bush and others. Such early electro-mechanical retrieval systems were later superseded by the development of digital computers.