Mel’nikT. A. “Asymptotic Behavior of Eigenvalues and Eigenfunctions of the Fourier Problem in a Thick Multilevel Junction”. Ukrains’kyi Matematychnyi Zhurnal 58, no. 2 (February 25, 2006): 195–216. Accessed November 22, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/3447.