@article{1077466403, author = {Williams, R. F.}, title = {Local properties of open mappings}, journal = {Duke Math. J.}, volume = {22}, number = {1}, year = {1955}, pages = { 339-345}, language = {en}, url = {http://dml.mathdoc.fr/item/1077466403} }
Williams, R. F. Local properties of open mappings. Duke Math. J., Tome 22 (1955) no. 1, pp. 339-345. http://gdmltest.u-ga.fr/item/1077466403/