ANDERSEN, Erik Sparre. Two summation formulae for product sums of binomial coefficients. Mathematica Scandinavica, Berkeley, CA, United States, v. 1, p. 261–262, 1953. DOI: 10.7146/math.scand.a-10384. Disponível em: https://journals.msp.org/mscand/article/view/2934. Acesso em: 25 jul. 2026.