@article{AUCMP_2007__48_2_a3,
     author = {Chodounsk\'y, David},
     title = {Non-normality and relative normality of {Niemytzki} plane},
     journal = {Acta Universitatis Carolinae. Mathematica et Physica},
     pages = {37--41},
     publisher = {mathdoc},
     volume = {48},
     number = {2},
     year = {2007},
     mrnumber = {2512900},
     zbl = {1157.54009},
     language = {en},
     url = {https://geodesic-test.mathdoc.fr/item/AUCMP_2007__48_2_a3/}
}