1. A commercial bibliographic database and retrieval service from DIALOG Information Services. 2. Interactive mathematics using a href="module.php?name=Lexikon&file=search&eid=1&query=graphics tablet">graphics tablet by Illinois Inst Tech, 1966. ["DIALOG: A Conversational Programming System with a Graphical Orientation", S.h. Cameron et al, CACM 10:349-357 (1967). Sammet 1969, p.255-258].