SANSONE, Fred J. The Backward and Forward Summation of Infinite Series of Isols. MATHEMATICA SCANDINAVICA, [S. l.], v. 24, p. 217–220, 1969. DOI: 10.7146/math.scand.a-10932. Disponível em: https://tidsskrift.dk/math/article/view/10932. Acesso em: 14 aug. 2026.