T. Maeda, N. Takiguchi, T. Morita, M. Ishikawa, and T. Hemsel, “Hydrothermal (K1-xNax)NbO3 Lead-free Piezoelectric Ceramics,” Journal of Korean Physical Society, vol. 57, no. 4, pp. 924–928, 2010.

T. Maeda, N. Takiguchi, T. Morita, M. Ishikawa, and T. Hemsel, “(K,Na)NbO3 lead-free piezoelectric ceramics synthesized from hydrothermal powders,” Materials Letters, vol. 64, no. 2, pp. 125–128, 2010.