Nguyen, T. T. H., Quyet, D. T., & Vu, T. H. A. (2023). Liouville type theorems for Kirchhoff sub-elliptic equations involving $\Delta_\lambda$-operators. Topological Methods in Nonlinear Analysis, 62(1), 327–340. https://doi.org/10.12775/TMNA.2022.071