[国外标准] SAE J1453-2002 Fitting.O-Ring Face Seal
[国外标准] JIS B8323-2003 Water ring vacuum pumps
[国外标准] JIS C2569-1998 Ring cores made of ferromagnetic oxide
[国外标准] JIS S4700-1998 Jewellery -- Ring-sizes -- Definition, measurement and designation