Methods of test for masonry units - Part 4: Determination of real and bulk density and of total and open porosity for natural stone masonry units; German version EN 772-4:1998— 6 стр.
91.100.15 Mineral. Including earth, sands, clay, slates, stones, etc. / Минеральные материалы и изделия. Включая землю, песок, глину, шифер, камень, кирпич и т.д.
