Basov, V.V. and Bibikov, Y.N. 2024. Normal form and stability of the zero solution of a second-order periodic invertible ODE with a small parameter. Vestnik of Saint Petersburg University. Mathematics. Mechanics. Astronomy. 11, 4 (Dec. 2024), 684–692. DOI:https://doi.org/10.21638/spbu01.2024.405.