V. T. Huong, Q. K. Quang, T. T. Thuy, P. D. Anh, N. V. Thanh, and N. A. Viet, “pH-Dependence of the Optical Bio-sensor Based on DNA-carbon Nanotube”, Comm. Phys., vol. 20, no. 4, p. 309, Nov. 2012.