@article{Ottnad:2014vc, author = "Ottnad, Konstantin and Urbach, Carsten and Michael, Chris", title = "{$\eta$ and $\eta'$ masses and decay constants from lattice QCD with $N_f=2+1+1$ quark flavours}", doi = "10.22323/1.187.0253", journal = "PoS", year = 2014, volume = "LATTICE 2013", pages = "253" }