For citations:

Amel‘kin V.V., Tyshchenko V.Yu. Isochronous centers and foci of two-dimensional holomorphic differential systems. Izvestiya Vysshikh Uchebnykh Zavedenii. Matematika. 2024;(11):3-11. (In Russ.) https://doi.org/10.26907/0021-3446-2024-11-3-11