Nihon Denshin Denwa Kōsha

• Dempō ryōkin no enkaku
• Denki tsūshin taisaku hōkokusho
• Jidō denwa kōkan nijūgonenshi
• Kaisen kōkan sābisu no intafēsu
• Nihon Denshin Denwa Kōsha kenchiku sakuhinshū
• Puroguramu gakushū ni yoru COBOL
• Ryōkin jimu
• Senyō denshin denwa ryōkin no enkaku
• 專用電信電話料金の沿革