Akhmet, M. U., M. K. Dauylbayev, A. E. Mirzakulova, and N. Atakhan. 2018. “Singularly Perturbed Linear Oscillator With Piecewise-Constant Argument”. Journal of Mathematics, Mechanics and Computer Science 97 (1):3-13. https://doi.org/10.26577/jmmcs-2018-1-480.