WANG, JianFeng, BELARDO, Francesco, HUANG, Qiongxiang and LI MARZI, Enzo M., 2010, Spectral characterizations of dumbbell graphs. [online]. 2010. Vol. 17. [Accessed 2 April 2025]. Retrieved from: http://www.combinatorics.org/ojs/index.php/eljc/article/view/v17i1r42/pdf