@article{GMJ_2002__9_1_50810,
     author = {Bricchi, Michele},
     title = {Existence and properties of -sets.},
     journal = {Georgian Mathematical Journal},
     pages = {13--32},
     publisher = {mathdoc},
     volume = {9},
     number = {1},
     year = {2002},
     zbl = {1040.28008},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/GMJ_2002__9_1_50810/}
}