P. M. Tan, N. V. Khoi, T. V. Thang, N. V. manh, and H. T. Phuong, “Studying reactivity ratios and physical properties of n-vinyl pyrrolidone-N,N’-dimethylacrylamide copolymer”, VJChem, vol. 54, no. 2, p. 213, Jul. 2016.