Hansen, A. K., and M. Kudeyt. “Controllability of Affine Systems on Free Nilpotent Lie Groups Gm,?”. Proyecciones (Antofagasta, On Line), vol. 38, no. 3, Aug. 2019, pp. 499-0, doi:10.22199/issn.0717-6279-2019-03-0032.