Brunner, T., Lapierre, A., Andreoiu, C., Brodeur, M., Delheji, P., Ettenauer, S., et al. (2013). Trapped-ion decay spectroscopy towards the determination of ground-state components of double-beta decay matrix elements. European Physical Journal A, 49(11): 142, pp. 1-9. doi:10.1140/epja/i2013-13142-4.