Non-perturbative pion dynamics for the X(3872)V. Baru, E. Epelbaum, A. A. Filin, C. Hanhart, A. E. Kudryavtsev, Yu. S. Kalashnikova, U.-G. Meißner and A. V. NefedievEPJ Web of Conferences, 81 (2014) 05005DOI: https://doi.org/10.1051/epjconf/20148105005