1. D. Cvetković, M. Doob, H. Sachs,Spectra of graphs—Theory and applications, 3rd rerised and enlarged edition, J.A. Barth Verlag, Heidelberg-Leipzig, 1995.
2. Godsil C.D., McKay B.D.A new graph product and its spectrum. Bull., Austral. Math. Soc., 18 (1978), 21–28.
3. R. Grone, R. Merris, V. S. SunderThe Laplacian spectrum of a graph, SIAM J. Matrix Anal. Appl., 11 (1990), 218–238.
4. M. Lepović, I. GutmanNo starlike trees are cospectrul, Discrete Math., 242 (2002), 291–295.
5. M. Lepović, I. Gutman, M. PetrovicOn canonical graphs and the Laplacian characteristic polynomial, Univ. Beograd Publ. Elektro-tehn. Fak., (Ser. Mat.) 11 (2000), 93–99.