Gully tops and manhole tops for vehicular and pedestrian areas – Securing of the cover or grating within the frame
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 09/01/2015

Masses per unit area for gully tops and manhole tops for vehicular and pedestrian areas
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 06/01/1996