MenkоY. P. “Method of Determining Intervals of Instability of Quasiharmonic Systems With a Delayed Argument”. Ukrains’kyi Matematychnyi Zhurnal 18, no. 2 (March 5, 1966): 129-135. Accessed November 24, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/8727.