@article{CMUC_2004_45_3_a11,
     author = {Osba, Emad Abu and Henriksen, Melvin},
     title = {Essential $P$-spaces: a generalization of door spaces},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {509--518},
     year = {2004},
     volume = {45},
     number = {3},
     mrnumber = {2103145},
     zbl = {1100.54024},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_2004_45_3_a11/}
}