Yeo, Dong-Hun, et al. “Microwave Dielectric Properties of Low-Temperature Sintered Bi2[Zn1 3(Nb1-xTax)2 3]2O7”. Asian Journal of Chemistry, vol. 26, no. 5, Mar. 2014, pp. 1549-52, doi:10.14233/ajchem.2014.17284.