K. A. Makarov, S. Belyi, and E. Tsekanovskii, “Conservative L-systems and the Livšic function”, MFAT, vol. 21, no. 2, pp. 104–133, Jun. 2015, Accessed: Dec. 16, 2025. [Online]. Available: https://zen.imath.kiev.ua/index.php/mfat/article/view/606