Robles-Águila, M.J., Luna-López, J.A., Hernández de la Luz, Á.D., Martínez-Juárez, J., Rabanal, M.E. (2018). Synthesis and Characterization of Nanocrystalline ZnO Doped with Al3+ and Ni2+ by a Sol–Gel Method Coupled with Ultrasound Irradiation. Crystals, 8 (11), 406.