Ferrite cores - Guidelines on dimensions and the limits of surface irregularities - Part 13: PQ-cores (IEC 63093-13:2019); German version EN IEC 63093-13:2019— 24 стр.
Terms and nomenclature for cores made of magnetically soft ferrites - Part 1: Terms used for physical irregularities and reference of dimensions (IEC 51/1276/CD:2019); Text in German and English