Revealing the non-s2 contributions in the momentum wave function of ground-state 
H. Schmidt-Böcking, V. Mergel, R. Dörner, C. L. Cocke, O. Jagutzki, L. Schmidt, Th. Weber, H. J. Lüdde, E. Weigold, J. Berakdar, H. Cederquist, H. T. Schmidt, R. Schuch and A. S. Kheifets
Europhys. Lett., 62 4 (2003) 477-483
DOI: https://doi.org/10.1209/epl/i2003-00378-5