PivovarchikV., and ChernyshenkoA. “Cospectral Quantum Graphs in the Case of Dirichlet Conditions at Pendant Vertices”. Ukrains’kyi Matematychnyi Zhurnal 75, no. 3 (April 11, 2023): 382 - 396. Accessed September 1, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/7351.