@article{PORMA_1954__13_3_114738,
     author = {Halfar, Edwin},
     title = {The isolated points of a set},
     journal = {Portugaliae mathematica},
     pages = {125--128},
     publisher = {mathdoc},
     volume = {13},
     number = {3},
     year = {1954},
     mrnumber = {0072457},
     zbl = {0057.38703},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1954__13_3_114738/}
}