DIN 53120-1
DIN 53120-1 Testing of paper and board - Determination of air permeability - Part 1: Medium rate of air permeability according to Bendtsen
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 06/01/1998
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 06/01/1998