MOSSIGE, Svein. On extremal $h$-bases $A_4$. MATHEMATICA SCANDINAVICA, [S. l.], v. 61, p. 5–16, 1987. DOI: 10.7146/math.scand.a-12188. Disponível em: https://tidsskrift.dk/math/article/view/12188. Acesso em: 14 aug. 2026.