NF A49-540-2:2006 Cold formed welded structural hollow sections of non-alloy and fine grain steels - Part 2 : tolerances, dimensions and sectional properties.
2006NF A49-540-2:2006 Cold formed welded structural hollow sections of non-alloy and fine grain steels - Part 2 : tolerances, dimensions and sectional properties.
1997NF A49-540-2:1997 Cold form welded structural hollow sections of non-alloy and fine grain steels. Part 2 : tolerances, dimensions and sectional properties.