Dispersive analysis for η→γγ ⋆ C. Hanhart, A. Kupść, U.-G. Meißner, F. Stollenwerk and A. Wirzba Eur. Phys. J. C, 73 12 (2013) 2668 Published online: 11 December 2013 DOI: 10.1140/epjc/s10052-013-2668-3