DIN EN 61811-1-2015 质量评估的机电式电信基本继电器. 第1部分: 总规格和空白详细规格 (IEC 61811-1-2015); 德文版本EN 61811-1-2015
Electromechanical telecom elementary relays of assessed quality - Part 1: Generic specification and blank detail specification (IEC 61811-1:2015); German version EN 61811-1:2015