Er’omenko, V.O. and Aliluiko, A.M. (2010) “Quasiperiodic solutions of degenerate linear systems of second-order ordinary differential equations”, Ukrains’kyi Matematychnyi Zhurnal, 62(6), pp. 773–783. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/2908 (Accessed: 10 April 2025).