Dukat, Monika, and Aldona Zarycka. “Dielectric and Piezoelectric Properties of PZT Type Ceramics Obtained by the Sol-Gel Method”. Archives of Acoustics, vol. 32, no. 4(S), Jan. 2014, pp. 65-70, https://acoustics3.ippt.pan.pl/index.php/aa/article/view/1390.