Serrano, T., and I. Gómez. “One Pot Synthesis of PbS/Cu$_{2}$S Core-Shell Nanoparticles and Their Optical Properties”. Revista Mexicana De Física, vol. 60, no. 1 Jan-Feb, Jan. 2014, pp. 14-0, https://rmf.smf.mx/ojs/index.php/rmf/article/view/4046.