T. I. Ushchapivska, I. V. Zatovsky, M. S. Slobodyanik, and R. M. Kuzmin, “Conductive properties of solid solutions Na3????2xFe2????xNbx(PO4)3 (x = 0  1:5)”, Dopov. Nac. akad. nauk Ukr., no. 5, pp. 95–100, Oct. 2024.