Non-perturbative treatment of the linear covariant gauges by taking into account the Gribov copies M. A. L. Capri, A. D. Pereira, R. F. Sobreiro and S. P. Sorella Eur. Phys. J. C, 75 10 (2015) 479 Published online: 06 October 2015 DOI: 10.1140/epjc/s10052-015-3707-z