RYS, P.; ZDRÁHAL, T. Slow divergence of the harmonic series. Annales Universitatis Paedagogicae Cracoviensis Studia Mathematica, [S. l.], v. 3, p. 233–235, 2003. Disponível em: https://studmath.uken.krakow.pl/article/view/13494. Acesso em: 30 oct. 2026.