Antiproton–to–electron mass ratio determined by two-photon laser spectroscopy of antiprotonic helium atomsA. Sótér, M. Hori, D. Barna, R. Hayano, A. Dax, S. Friedreich, B. Juhász, T. Pask, E. Widmann, D. Horváth, L. Venturelli and N. ZurloEPJ Web of Conferences, 66 (2014) 05020DOI: https://doi.org/10.1051/epjconf/20146605020