[1]
V. N. Pivovarchik and O. Martinyuk, “Spectral problem for figure-of-eight graph of Stieltjes strings”, MFAT, vol. 16, no. 4, pp. 349–358, Dec. 2010, Accessed: Dec. 16, 2025. [Online]. Available: https://zen.imath.kiev.ua/index.php/mfat/article/view/462