@article{PIM_1998_N_S_63_77_a4,
     author = {Ivan Gutman},
     title = {Distance of {Thorny} {Graphs}},
     journal = {Publications de l'Institut Math\'ematique},
     pages = {31 },
     publisher = {mathdoc},
     volume = {_N_S_63},
     number = {77},
     year = {1998},
     zbl = {0942.05021},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PIM_1998_N_S_63_77_a4/}
}