Ostrovskii, V. L., & Samoilenko, Y. S. (2006). On spectral theorems for families of linearly connected self-adjoint operators with given spectra associated with extended Dynkin graphs. Ukrains’kyi Matematychnyi Zhurnal, 58(11), 1556–1570. Retrieved from https://umj.imath.kiev.ua/index.php/umj/article/view/3554