DIN 55626-20
DIN 55626-20 Extenders and pigments for paper and board - Specifications and methods of test - Part 20: Fumed silica
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 07/01/2007
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 07/01/2007