A.S. Kovalev, Y.E. Prilepskii, and K.A. Gradjushko, Dynamics of pair of coupled nonlinear systems. I. Magnetic systems, Low Temp. Phys. 46, (2020) [Fiz. Nizk. Temp. 46, 1014-1020, (2020)] DOI: https://doi.org/10.1063/10.0001554.