Neutron-proton mass difference in finite nuclei and the Nolen-Schiffer anomalyU. -G. Meißner, A. M. Rakhimov, A. Wirzba and U. T. YakhshievEur. Phys. J. A, 36 1 (2008) 37-48DOI: https://doi.org/10.1140/epja/i2008-10571-0