Zemach and magnetic radius of the proton from the hyperfine splitting in hydrogen A. V. Volotka, V. M. Shabaev, G. Plunien and G. Soff Eur. Phys. J. D, 33 1 (2005) 23-27 Published online: 15 February 2005 DOI: 10.1140/epjd/e2005-00025-9