Пьяных, Б. Е. “Inversion of Frequency in Key Schemes for Airborne Power Systems”. Proceedings of National Aviation University (archive) 6, no. 1-2 (September 20, 2000): 153–158. Accessed April 13, 2026. http://jrnl.kai.edu.ua/index.php/visnik/article/view/9735.