| http://www.w3.org/ns/prov#value | - Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS3940758 *Sep 20, 1974Feb 24, 1976Margolin George DExpandable keyboard for electronic pocket calculators and the likeUS4378553 *Mar 13, 1981Mar 29, 1983Mccall William CData input system using a split keyboardUS4661005 *Jan 16, 1984Apr 28, 1987Creative AssociatesSpittable keyboard for word processing, typing and other information
|
