Akhmetova О. and Issayev, S. 2025. STATIONARY DIFFUSION MODEL IN HETEROGENEOUS MEDIA WITH SMALL PARAMETERS. Bulletin of Abai KazNPU. Series of Physical and Mathematical sciences. 90, 2 (Jun. 2025), 18–35. DOI:https://doi.org/10.51889/2959-5894.2025.90.2.002.