Tau mass measurement at BES-III M.N. Achasov, X.H. Mo, N.Yu. Muchnoi, I.B. Nikolaev, S.A. Privalov and J.Y. Zhang EPJ Web Conf., 212 (2019) 08005 Published online: 17 June 2019 DOI: 10.1051/epjconf/201921208005