Koshlyakov, V. N., and V. L. Makarov. “Structural Analysis of One Class of Dynamical Systems”. Ukrains’kyi Matematychnyi Zhurnal, vol. 52, no. 8, Aug. 2000, pp. 1089-96, https://umj.imath.kiev.ua/index.php/umj/article/view/4512.