@article{BMMS_2013_36_1_a8,
     author = {Xueliang Li and Yiyang Li},
     title = {The {Asymptotic} {Behavior} of the {Estrada} {Index} for {Trees}},
     journal = {Bulletin of the Malaysian Mathematical Society},
     year = {2013},
     volume = {36},
     number = {1},
     url = {http://geodesic.mathdoc.fr/item/BMMS_2013_36_1_a8/}
}