1999JB/T 9843-1999 EIectromagnetic ammeter for tractors and internal combustion engines
1981NJ 240-1981 Electromagnetic ammeter for tractor and internal combustion engine
NJ 240-1981 Electromagnetic ammeter for tractor and internal combustion engine was changed to JB/T 9843-1999 EIectromagnetic ammeter for tractors and internal combustion engines.