PACHPATTE, B. G. ON LYAPUNOV TYPE FINITE DIFFERENCE INEQUALITY. Tamkang Journal of Mathematics, [S. l.], v. 21, n. 4, p. 337–339, 1990. DOI: 10.5556/j.tkjm.21.1990.4678. Disponível em: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/4678. Acesso em: 18 aug. 2022.