The mass composition of cosmic rays measured with LOFAR Jörg R. Hörandel, A. Bonardi, S. Buitink, A. Corstanje, H. Falcke, P. Mitra, K. Mulrey, A. Nelles, J.P. Rachen, L. Rossetto et al. (6 more) EPJ Web Conf., 136 (2017) 02001 Published online: 23 March 2017 DOI: 10.1051/epjconf/201713602001