2 citations to https://www.mathnet.ru/rus/tvp4209

1. Hung T.L. Kien Ph.T., “On the Order of Approximation in Limit Theorems For Negative-Binomial Sums of Strictly Stationary M-Dependent Random Variables”, Acta Math. Vietnam, 46:1 (2021), 203–224      
2. Tran Loc Hung Phan Tri Kien, “An Extension of Zolotarev'S Problem and Some Related Results”, Acta Math. Sci., 41:5 (2021), 1619–1634