Hadronic contribution of light by light scattering in the energy spectrum of muonic hydrogen A. E. Dorokhov, A. P. Martynenko, F. A. Martynenko and A. E. Radzhabov EPJ Web Conf., 204 (2019) 05008 Published online: 03 April 2019 DOI: 10.1051/epjconf/201920405008