G. Aad, B. Abbott, J. Abdallah, O. Abdinov, R. Aben, K. Augsten, P. Gallus, J. Guenther, J. Jakůbek, Z. Kohout et al.: Search for production of vector-like quark pairs and of four top quarks in the lepton-plus-jets final state in pp collisions at root 8=8 TeV with the ATLAS detector. Journal of High Energy Physics 2015(8), 105 (2015). doi:10.1007/JHEP08(2015)105