POTRA, F. .- a.; PTÁK, V. Nondiscrete induction and double step secant method. MATHEMATICA SCANDINAVICA, [S. l.], v. 46, p. 236–250, 1980. DOI: 10.7146/math.scand.a-11866. Disponível em: https://www.mscand.dk/article/view/11866. Acesso em: 7 may. 2024.