@article{MABA_1991_5_4_a7,
     author = {Janusz J. Charatonik},
     title = {Conditions {Related} to {Selectibility}},
     journal = {Mathematica balkanica},
     pages = {359},
     year = {1991},
     volume = {5},
     number = {4},
     url = {http://geodesic.mathdoc.fr/item/MABA_1991_5_4_a7/}
}