SCHWARZ, W. Remarks on the Irrationality and Transcendence of Certain Series. MATHEMATICA SCANDINAVICA, [S. l.], v. 20, p. 269–274, 1967. DOI: 10.7146/math.scand.a-10836. Disponível em: https://www.mscand.dk/article/view/10836. Acesso em: 4 may. 2024.