@article{MZ_1966__94_170633,
     author = {Frank Harary and Michael D. Plummer},
     title = {On the {Point-Core} of a {Graph.}},
     journal = {Mathematische Zeitschrift},
     pages = {382--386},
     publisher = {mathdoc},
     volume = {94},
     year = {1966},
     zbl = {0144.45404},
     url = {http://geodesic.mathdoc.fr/item/MZ_1966__94_170633/}
}