KIRFEL, Christoph; SELMER, Ernst S. Regular $h$-ranges and weakly pleasant $h$-bases. MATHEMATICA SCANDINAVICA, [S. l.], v. 59, p. 30–40, 1986. DOI: 10.7146/math.scand.a-12151. Disponível em: https://www.mscand.dk/article/view/12151. Acesso em: 5 dec. 2025.