FENYŐ, I.; PAP, E. ON THE FUNCTIONAL EQUATION f(x1 )+f(x2) = f(Y1) +f(Y2). Periodica Polytechnica Electrical Engineering, [S. l.], v. 25, n. 2, p. 115–122, 1981. Disponível em: https://pp.bme.hu/ee/article/view/4772. Acesso em: 16 apr. 2025.