Islands of stability of the d-wave order parameter in s-wave anisotropic superconductors R. Gonczarek, M. Krzyzosiak and A. Gonczarek Eur. Phys. J. B, 61 3 (2008) 299-308 Published online: 22 February 2008 DOI: 10.1140/epjb/e2008-00072-6