@article{RM_1990_45_6_a22,
     author = {V. Sh. Yusufov},
     title = {Open openly covering maps},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {175--176},
     publisher = {mathdoc},
     volume = {45},
     number = {6},
     year = {1990},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1990_45_6_a22/}
}