@article{KJM_2010_34_1_a11,
     author = {Singaraj K. Ayyaswamy and Selvaraj Balachandran and Ivan Gutman},
     title = {On second-stage spectrum and energy of a graph},
     journal = {Kragujevac Journal of Mathematics},
     pages = {139 - 146},
     publisher = {mathdoc},
     volume = {34},
     number = {1},
     year = {2010},
     url = {http://geodesic.mathdoc.fr/item/KJM_2010_34_1_a11/}
}