@article{10_21136_CPM_1987_118295,
     author = {Ryj\'a\v{c}ek, Zden\v{e}k},
     title = {On graphs with isomorphic, non-isomorphic and connected $N_2$-neighbourhoods},
     journal = {\v{C}asopis pro p\v{e}stov\'an{\'\i} matematiky},
     pages = {66--79},
     publisher = {mathdoc},
     volume = {112},
     number = {1},
     year = {1987},
     doi = {10.21136/CPM.1987.118295},
     mrnumber = {880933},
     zbl = {0619.05041},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CPM.1987.118295/}
}