Signatures of bulk topology in the non-linear optical spectra of Dirac-Weyl materials Upendra Kumar, Vipin Kumar, Enamullah and Girish S. Setlur Eur. Phys. J. B, 91 5 (2018) 86 Published online: 21 May 2018 DOI: 10.1140/epjb/e2018-80559-1