Grechko, A.L. (1998) “On necessary conditions for the weak regularity of a linear extension of a dynamical system on a torus”, Ukrains’kyi Matematychnyi Zhurnal, 50(3), pp. 424–425. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/4942 (Accessed: 10 April 2025).