  In this paper, we give sufficient conditions on the spectral radius for a
bipartite graph to Hamiltonian and traceable, which expand the results of Lu,
Liu and Tian (2012) [10]. Furthermore, we also present tight sufficient
conditions on the signless Laplacian spectral radius for a graph to Hamiltonian
and traceable, which improve the results of Yu and Fan (2012) [12].
