On the second largest eigenvalue of line graphs
Miroslav Petrovi, Bojana Mileki · Journal of Graph Theory · 1998
In this paper all connected line graphs whose second largest eigenvalue does not exceed 1 are characterized. Besides, all minimal line graphs with second largest eigenvalue greater than 1 are determined. © 1998 John Wiley & Sons, Inc. J Graph Theory 27: 61–66, 1998