Building hardware – Lever handle units for fire doors and smoke control doors – Concepts and definitions, dimensions, requirements and testing
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 12/01/1997

Building hardware – Lever handle units for fire doors and smoke control doors – Terms and definitions, dimensions, requirements, testing and marking
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 07/01/2015