@article{PORMA_1967__26_2_115009,
     author = {Dickman, R.F. jr.},
     title = {On openness properties of mappings},
     journal = {Portugaliae mathematica},
     pages = {115--123},
     publisher = {mathdoc},
     volume = {26},
     number = {2},
     year = {1967},
     mrnumber = {0248765},
     zbl = {0186.56204},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1967__26_2_115009/}
}