BUNDSCHUH, P.; ZUDILIN, W. Irrationality measures for certain $q$-mathematical constants. MATHEMATICA SCANDINAVICA, [S. l.], v. 101, n. 1, p. 104–122, 2007. DOI: 10.7146/math.scand.a-15034. Disponível em: https://www.mscand.dk/article/view/15034. Acesso em: 29 mar. 2024.