Anisotropic Dirac cones in monoatomic hexagonal lattices: a DFT study A.M. Rojas-Cuervo, K.M. Fonseca-Romero and R.R. Rey-González Eur. Phys. J. B, 87 3 (2014) 67 Published online: 19 March 2014 DOI: 10.1140/epjb/e2014-40894-9