Bose-Einstein condensates in 1D optical lattices - Compressibility, Bloch bands and elementary excitationsM. Krämer, C. Menotti, L. Pitaevskii and S. StringariEur. Phys. J. D, 27 3 (2003) 247-261DOI: https://doi.org/10.1140/epjd/e2003-00284-4