AL-SALAM, W. A. Note on a $q$-identity. Mathematica Scandinavica, Berkeley, CA, United States, v. 5, p. 202–204, 1957. DOI: 10.7146/math.scand.a-10495. Disponível em: https://journals.msp.org/mscand/article/view/2827. Acesso em: 25 jul. 2026.