Li, Shaobo, et al. “Microstructure, Piezoelectric and Dielectric Properties of Lead-Free Ceramics K0.475Na0.475Li0.05NbO3-CaZrO3-CuO”. Asian Journal of Chemistry, vol. 25, no. 10, May 2013, pp. 5753-5, doi:10.14233/ajchem.2013.OH82.