Modulational instability criteria for two-component Bose–Einstein condensates I. Kourakis, P. K. Shukla, M. Marklund and L. Stenflo Eur. Phys. J. B, 46 3 (2005) 381-384 Published online: 18 August 2005 DOI: 10.1140/epjb/e2005-00271-7