UNE-EN 772-9:1999/A1:2008 Methods of test for masonry units - Part 9: Determination of volume and percentage of voids and net volume of clay and calcium silicate masonry units by sand filling
2008UNE-EN 772-9:1999/A1:2008 Methods of test for masonry units - Part 9: Determination of volume and percentage of voids and net volume of clay and calcium silicate masonry units by sand filling
1999UNE-EN 772-9:1999 Methods of test for masonry units - Part 9: Determination of volume and percentage of voids and net volume of clay and calcium silicate masonry units by sand filling