<?xml version="1.0"?>
<response><item key="0"><nothing>W. N&#xF6;rtersh&#xE4;user, J. Ullmann, L. V. Skripnikov, Z. Andelkovic, C. Brandau, A. Dax, W. Geithner, C. Geppert, C. Gorges, M. Hammen, V. Hannen, S. Kaufmann, K. K&#xF6;nig, F. Kraus, B. Kresse, Y. A. Litvinov, M. Lochmann, B. Maa&#xDF;, J. Meisner, T. Murb&#xF6;ck, A. F. Privalov, R. S&#xE1;nchez, B. Scheibe, M. Schmidt, S. Schmidt, V. M. Shabaev, M. Steck, T. St&#xF6;hlker, R. C. Thompson, C. Trageser, M. Vogel, J. Vollbrecht, &#x410;ndrey Volotka, C. Weinheimer, "The hyperfine puzzle of strong-field bound-state QED", Hyperfine Interactions, vol. 240, 2019, [DOI: 10.1007/s10751-019-1569-8] [SJR: 0.29]</nothing></item></response>
