Vacuum polarization in muonic and antiprotonic atoms: the fine structure at medium Z E. Yu. Korzinin, V. G. Ivanov and S. G. Karshenboim Eur. Phys. J. D, 41 1 (2007) 1-7 Published online: 05 August 2006 DOI: 10.1140/epjd/e2006-00181-4