Grigoriev, Y. et al. 2021. On Preliminary Group Classification of the Isotropic Boltzmann Equation with a Source Term in a Problem of Homogeneous Relaxation by Using Extended Equivalence Group. Journal of Vibration Testing and System Dynamics. 5, 3 (Sep. 2021), 259–267. DOI:https://doi.org/10.5890/JVTSD.2021.09.006.