@article{MMO_1988_51_a4,
     author = {V. V. Fedorchuk},
     title = {Multivalued retractions and characterizations of $n$-soft mappings},
     journal = {Trudy Moskovskogo matemati\v{c}eskogo ob\^{s}estva},
     pages = {169--207},
     publisher = {mathdoc},
     volume = {51},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MMO_1988_51_a4/}
}