EBANKS, Bruce R. On some functional equations of Jessen, Karpf, and Thorup. MATHEMATICA SCANDINAVICA, [S. l.], v. 44, p. 231–234, 1979. DOI: 10.7146/math.scand.a-11807. Disponível em: https://tidsskrift.dk/math/article/view/11807. Acesso em: 14 aug. 2026.