SANSONE, Fred J. The Backward and Forward Summation of Infinite Series of Isols. Mathematica Scandinavica, Berkeley, CA, United States, v. 24, p. 217–220, 1969. DOI: 10.7146/math.scand.a-10932. Disponível em: https://journals.msp.org/mscand/article/view/2368. Acesso em: 25 jul. 2026.