S.I. Melnyk, S.S. Melnyk, A.A. Lavrinovich, and N.T. Cherpak, Catastrophe theory in the phenomenological description of the avalanche effect in dc-biased microwave HTSC transmission lines: Superconductors at microwave frequencies and flux flow instabilities, Low Temp. Phys. 46, (2020) [Fiz. Nizk. Temp. 46, 433-440, (2020)] DOI: https://doi.org/10.1063/10.0000867.