Gap nodes and time reversal symmetry breaking in strontium ruthenate J. F. Annett, B. L. Györffy, G. Litak and K. I. Wysokiński Eur. Phys. J. B, 36 3 (2003) 301-312 Published online: 23 December 2003 DOI: 10.1140/epjb/e2003-00348-3