Phenomenological theory of the s-wave state in superconductors without an inversion center P. A. Frigeri, D. F. Agterberg, I. Milat and M. Sigrist Eur. Phys. J. B, 54 4 (2006) 435-448 Published online: 19 January 2007 DOI: 10.1140/epjb/e2007-00019-5