Oleksandr Bakai and Mykhailo Bratchenko, Stochastic dynamics of a nonlinear oscillator driven by periodic force with slowly varying frequency, Low Temp. Phys. 46, (2020) [Fiz. Nizk. Temp. 46, 899-903, (2020)] DOI: https://doi.org/10.1063/10.0001535.