DIRDAL, Gunnar. Congruences for the Fourier coefficients of certain modular forms. Mathematica Scandinavica, Berkeley, CA, United States, v. 39, p. 131–145, 1976. DOI: 10.7146/math.scand.a-11651. Disponível em: https://journals.msp.org/mscand/article/view/1995. Acesso em: 25 jul. 2026.