White dwarfs with a surface electrical charge distribution: equilibrium and stability G. A. Carvalho, José D. V. Arbañil, R. M. Marinho and M. Malheiro Eur. Phys. J. C, 78 5 (2018) 411 Published online: 24 May 2018 DOI: 10.1140/epjc/s10052-018-5901-2