@article {Aaboud:2016zpd,
	title = {{Measurements of top-quark pair to $Z$-boson cross-section ratios at $\sqrt s = 13, 8, 7$ TeV with the ATLAS detector}},
	journal = {JHEP},
	volume = {02},
	year = {2017},
	pages = {117},
	doi = {10.1007/JHEP02(2017)117},
	author = {Aaboud, Morad and others}
}
