Letter symbols to be used in electrical technology - Part 3: Logarithmic and related quantities, and their units (IEC 60027-3:2002); German version HD 60027-3:2004
Direct acting indicating analogue electrical measuring instruments and their accessories; part 1: definitions and general requirements common to all parts (IEC 60051-1:1984, edition 4); german version EN 60051-1:1989— 26 стр.