@article{2425, author = {Hammer, Preston C.}, title = {Extended topology: perfect sets}, journal = {Portugaliae mathematica}, volume = {23}, year = {1964}, pages = {27-34}, zbl = {0151.29301}, mrnumber = {0203663}, language = {en}, url = {http://dml.mathdoc.fr/item/2425} }
Hammer, Preston C. Extended topology: perfect sets. Portugaliae mathematica, Tome 23 (1964) pp. 27-34. http://gdmltest.u-ga.fr/item/2425/