Covariant extension of the GPD overlap representation at low Fock statesN. Chouika, C. Mezrag, H. Moutarde and J. Rodríguez-QuinteroEur. Phys. J. C, 77 12 (2017) 906DOI: https://doi.org/10.1140/epjc/s10052-017-5465-6