@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/