Ferrite cores - Guidelines on dimensions and the limits of surface irregularities - Part 12: Ring-cores (IEC 51/1227/CD:2018); Text in German and English
Ferrite cores - Guidelines on dimensions and the limits of surface irregularities - Part 12: Ring-cores (IEC 63093-12:2019); German version EN IEC 63093-12:2019— 20 стр.