The quark-gluon vertex and the QCD infrared dynamics Orlando Oliveira, Wayne de Paula, Tobias Frederico and J. P. B. C de Melo Eur. Phys. J. C, 79 2 (2019) 116 Published online: 06 February 2019 DOI: 10.1140/epjc/s10052-019-6617-7