Vol. 5 No. 3 (2016)

This issue includes five papers originating from subject matters presented at the XXI IMEKO World Congress 2015 held in Prague, during sessions organized by Technical Committee 21 on Mathematical Tools for Measurements, and selected for publication in Acta IMEKO. In the second part of this issue, further eight papers are published that were originally presented at other TC sessions of the 2015 World Congress and that are here presented in their extended versions.