Ferrite cores - Guide on the limits of surface irregularities - Part 3: ETD-cores and E-cores (IEC 60424-3:1999); German version EN 60424-3:1999— 10 стр.
Ferrite cores - Guidelines on dimensions and the limits of surface irregularities - Part 8: E-cores (IEC 63093-8:2018); German version EN IEC 63093-8:2018— 28 стр.