@article{1077489788, author = {Whyburn, G. T.}, title = {Semi-closed sets and collections}, journal = {Duke Math. J.}, volume = {2}, number = {1}, year = {1936}, pages = { 685-690}, language = {en}, url = {http://dml.mathdoc.fr/item/1077489788} }
Whyburn, G. T. Semi-closed sets and collections. Duke Math. J., Tome 2 (1936) no. 1, pp. 685-690. http://gdmltest.u-ga.fr/item/1077489788/