Vynnyk, D. M., and T. I. Voronyak. “Propagation of Microwave Ultrasonic Bulk Waves in Devices Based on Lithium Niobate Crystals”. Technology and Design in Electronic Equipment, no. 2, Apr. 2007, pp. 17-20, https://www.tkea.com.ua/index.php/journal/article/view/TKEA2007.2.17.