@article{KJM_2003_25_1_a3,
     author = {Ivan Gutman},
     title = {Graphs with smallest sum of squares of vertex degrees},
     journal = {Kragujevac Journal of Mathematics},
     pages = {51 - 54},
     year = {2003},
     volume = {25},
     number = {1},
     zbl = {1052.05024},
     url = {http://geodesic.mathdoc.fr/item/KJM_2003_25_1_a3/}
}