IEC 61326-2-3:2012-Electrical equipment for measurement, IEC 61061-3-1:1998-Non-impregnated densified laminated wood for electrical purposes-Part 3: Specifications for individual materials-Sheet 1: Sheets produced from beech veneer, IEC 61181:2007-Mineral oil-filled electrical equipment-Application of dissolved gas analysis (DGA) to factory tests o