Spectral boundary conditions and solitonic solutions in a classical Sellmeier dielectric F. Belgiorno, S. L. Cacciatori and A. Viganò Eur. Phys. J. C, 77 6 (2017) 404 Published online: 17 June 2017 DOI: 10.1140/epjc/s10052-017-4975-6