KISELEV, A. V.; ERSHOVA, Yu. Trace formulae for graph Laplacians with applications to recovering matching conditions. Methods of Functional Analysis and Topology, [S. l.], v. 18, n. 4, p. 343–359, 2012. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/526. Acesso em: 16 dec. 2025.