Velychko, Oleh, Sergii Shevkun, Tetyana Gordiyenko, and Oleh Mescheriak. 2018. “Interlaboratory Comparisons of the Calibration Results of Time Meters”. Eastern-European Journal of Enterprise Technologies 1 (9 (91):4-11. https://doi.org/10.15587/1729-4061.2018.121089.