* قائمة العمليات المكررة== المراجع ==* U. of FLA News* NCR Pads Ltd* Business Weeks Expose'* A Paper Trail== وصلات خارجية ==* Patent: Pressure-sensitive record material*Hazard Review: Carbonless Copy Paper, from the National Institute for Occupational Safety and Health.
==See also==* Spirit duplicator AKA Ditto machine* List of duplicating processes==Notes====References==* Original Patent US2730457 A* U. of FLA News* NCR Pads Ltd* Business Weeks Expose'* A Paper Trail==External links==*Patent: Pressure-sensitive record material*Hazard Review: Carbonless Copy Paper, from the National Institute for Occupational Safety and Health.