L. Zhu, Z.-D. Meng, C.-Y. Park, T. Ghosh, and W.-C. Oh, “Hydrothermal Synthesis and Visible Light Photocatalytic Behaviour of Ag2S and Ag2S-TiO2 Nanoparticles”, ajc, vol. 25, no. 2, pp. 726–730, Sep. 2012.