@article{2248, author = {Halfar, Edwin}, title = {The isolated points of a set}, journal = {Portugaliae mathematica}, volume = {13}, year = {1954}, pages = {125-128}, zbl = {0057.38703}, mrnumber = {0072457}, language = {en}, url = {http://dml.mathdoc.fr/item/2248} }
Halfar, Edwin. The isolated points of a set. Portugaliae mathematica, Tome 13 (1954) pp. 125-128. http://gdmltest.u-ga.fr/item/2248/