G. Aad, T. Abajyan, B. Abbott, S.A. Khalek, O. Abdinov, K. Augsten, P. Gallus, J. Günther, J. Jakůbek, Z. Kohout et al.: Search for dark matter in events with a Z boson and missing transverse momentum in pp collisions at root s=8 TeV with the ATLAS detector. Physical Review D 90(1), 012004 (2014). doi:10.1103/PhysRevD.90.012004