|Note_en=Scanning of a June 1920 [[Sheaffer]] advertising for a mechanical pencil (CAS). Published on ''The National Geographic Magazine'' Vol. XXXVII, Nr. 6. | |Note_en=Scanning of a June 1920 [[Sheaffer]] advertising for a mechanical pencil (CAS). Published on ''The National Geographic Magazine'' Vol. XXXVII, Nr. 6. |