Sakhnovich, L.A. (1997) “Spectral problems for canonical systems of finite-difference equations on an axis”,
Ukrains’kyi Matematychnyi Zhurnal, 49(6), pp. 779–788. Available at:
https://umj.imath.kiev.ua/index.php/umj/article/view/5062 (Accessed: 14 April 2025).