1. Agmon S. On positivity and decay of solutions of second order elliptic equations on Riemannian manifolds. In: Methods of Functional Analysis and Theory of Elliptic Equations. Naples: Liguori, 1983, 19–52
2. Alarcón S, García-Melián J, Quaas A. Optimal Liouville theorems for supersolutions of elliptic equations with the Laplacian. Ann Sc Norm Super Pisa Cl Sci (5), 2016, 16: 129–158
3. Armstrong S, Sirakov B. Nonexistence of positive supersolutions of elliptic equations via the maximum principle. Comm Partial Differential Equations, 2011, 36: 2011–2047
4. Armstrong S, Sirakov B. Sharp Liouville results for fully nonlinear equations with power-growth nonlinearities. Ann Sc Norm Super Pisa Cl Sci (5), 2011, 10: 711–728
5. Bae S, Kwon O. Nonexistence of positive solutions of nonlinear elliptic systems with potentials vanishing at infinity. Nonlinear Anal, 2012, 75: 4025–4032