@article{Sopuev2020absolute,
author={Sopuev, U.A. and Keldibekova, A.O.},
title={Absolute Value of Number in Mathematical Olympiads Tasks},
journal={Profession-Oriented School},
publisher={INFRA-M Academic Publishing LLC.},
year={2020},
pages={44-50},
volume={8},
issue={1},
}