DIN EN 60061-2/E21:2007
Lamp caps and holders together with gauges for the control of interchangeability and safety- Part 2: Lampholders (IEC 60061-2-1969+supplements A:1970 to S:1997+A18:1998 to A35:2006, modified); German version EN 60061-1:1993+A1:1995 to A7:1997+A18:1988 t