Central exclusive production as a probe of the gluonic component of the η′ and η mesonsThe KRYSTHAL Collaboration, L. A. Harland-Lang, V. A. Khoze, M. G. Ryskin and W. J. StirlingEur. Phys. J. C, 73 5 (2013) 2429DOI: https://doi.org/10.1140/epjc/s10052-013-2429-3