COHEN, Edward L. The Diophantine equation $x^2+11=3^k$ and related questions. Mathematica Scandinavica, Berkeley, CA, United States, v. 38, p. 240–246, 1976. DOI: 10.7146/math.scand.a-11631. Disponível em: https://journals.msp.org/mscand/article/view/2016. Acesso em: 25 jul. 2026.