@article{ZR_2009_13_21_a5,
     author = {Hanyuan Deng and Slavko Radenkovi\'c and Ivan Gutman},
     title = {The {Estrada} {Index}},
     journal = {Zbornik radova},
     pages = {123 },
     publisher = {mathdoc},
     volume = {13},
     number = {21},
     year = {2009},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ZR_2009_13_21_a5/}
}