SCHWARZ, Wolfgang. Remarks on the Irrationality and Transcendence of Certain Series. Mathematica Scandinavica, Berkeley, CA, United States, v. 20, p. 269–274, 1967. DOI: 10.7146/math.scand.a-10836. Disponível em: https://journals.msp.org/mscand/article/view/2490. Acesso em: 25 jul. 2026.