Banakh, T., Sheremeta, M., Skaskiv, O. and Zarichnyi, M. 2025. Ihor Guran (in honour of the 70th anniversary of birth). Matematychni Studii. 63, 1 (Mar. 2025), 108-112. DOI:https://doi.org/10.30970/ms.63.1.108-112.