Two-photon coincidence studies of highly-charged ion relaxation in solids Z. D. Pešić, Gy. Vikor, H. Hanafy, A. Enulescu and R. Schuch Eur. Phys. J. D, 54 3 (2009) 623-628 Published online: 17 July 2009 DOI: 10.1140/epjd/e2009-00206-6