@article{MZM_2001_70_2_a0,
     author = {M. V. Balashov},
     title = {Geometric {Difference} of {Multivalued} {Maps}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {163--169},
     publisher = {mathdoc},
     volume = {70},
     number = {2},
     year = {2001},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2001_70_2_a0/}
}