Instabilities and the roton spectrum of a quasi-1D Bose-Einstein condensed gas with dipole-dipole interactionsS. Giovanazzi and D. H.J. O'DellEur. Phys. J. D, 31 2 (2004) 439-445DOI: https://doi.org/10.1140/epjd/e2004-00146-7