@article{MABA_1990_4_1_a1,
     author = {D. Cirich and Z. Mijajlovich},
     title = {Topologies on {Classes}},
     journal = {Mathematica balkanica},
     pages = {10},
     year = {1990},
     volume = {4},
     number = {1},
     url = {http://geodesic.mathdoc.fr/item/MABA_1990_4_1_a1/}
}