HE, X.-G.; LIU, C.-T. On the range of ∑n=1∞ ±cn. Annales Fennici Mathematici, [S. l.], v. 40, n. 1, p. 135–148, 2015. DOI: 10.5186/aasfm.2015.4004. Disponível em: https://afm.journal.fi/article/view/135533. Acesso em: 30 oct. 2024.