Ground-state energy of pionic hydrogen to one loop J. Gasser, M.A. Ivanov, E. Lipartia, M. Mojžiš and A. Rusetsky Eur. Phys. J. C, 26 1 (2002) 13-34 Published online: 09 October 2002 DOI: 10.1007/s10052-002-1013-z