The spectrum of neighborhood corona of graphs Indulal Gopalapillai — 2011 Kragujevac Journal of Mathematics
Spectrum of two new joins of graphs and infinite families of integral graphs Gopalapillai Indulal — 2012 Kragujevac Journal of Mathematics
D -equienergetic self-complementary graphs Gopalapillai Indulal; Ivan Gutman — 2009 Kragujevac Journal of Mathematics