GOULD, H. W. The $q$-Series Generalization of a Formula of Sparre Andersen. Mathematica Scandinavica, Berkeley, CA, United States, v. 9, p. 90–94, 1961. DOI: 10.7146/math.scand.a-10626. Disponível em: https://journals.msp.org/mscand/article/view/2715. Acesso em: 25 jul. 2026.