BANERJEE, A.; CHAKRABORTY, B. Further investigations on a question of Zhang and Lü. Annales Universitatis Paedagogicae Cracoviensis Studia Mathematica, [S. l.], v. 14, p. 105–119, 2015. Disponível em: https://studmath.uken.krakow.pl/article/view/13157. Acesso em: 31 oct. 2026.