Loc Hung, T., Kien, P. and Tan Nhut, N. 2020. Asymptotic behaviors with convergence rates of distributions of negative-binomial sums. Science and Technology Development Journal. 22, 4 (Jan. 2020), 415-421. DOI:https://doi.org/https://doi.org/10.32508/stdj.v22i4.1689.