@article{Kazaryan2015ultrasonic,
author={Kazaryan, A.. and Bodaeva, M.. and Kovalev, I..},
title={Ultrasonic hardness tester},
journal={Actual directions of scientific researches of the XXI century: theory and practice},
publisher={FSBE Institution of Higher Education Voronezh State University of Forestry and Technologies named after G.F. Morozov},
year={2015},
pages={155-158},
volume={3},
issue={7},
}