Tkachenko, V. I. “On Reducibility of Systems of Linear Differential Equations With Quasiperiodic Skew-Adjoint Matrices”. Ukrains’kyi Matematychnyi Zhurnal 54, no. 3 (March 25, 2002): 419–424. Accessed December 5, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/4079.