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Ashburn, J.R. and Cline, R.A. and van der Burgt, P.J.M. and Westerveld, W.B. and Risley, J.S. (1990) Experimentally determined density matrices for H(n=3) formed in H+-He collisions from 20 to 100 keV. Physical Review A, 41 (5). pp. 2407-2421. ISSN 1050-2947