Safety of machinery - Basic concepts, general principles for design - Part 2: Technical principles and specifications; German version EN 292-2:1991 + A1:1995— 47 стр.
Fibre optic communication subsystem test procedures - Part 2-9: Digital systems; Optical signal-to-noise ratio measurement for dense wavelength-division multiplexed systems (IEC 61280-2-9:2002); German version EN 61280-2-9:2002— 16 стр.