@article{DAN_1957_114_3_a5,
     author = {Ludmila Keldysh},
     title = {Transformation of a monotone irreducible mapping into a monotone-interior mapping and a monotone-interior 
},
     journal = {Doklady Akademii Nauk},
     pages = {472--475},
     publisher = {mathdoc},
     volume = {114},
     number = {3},
     year = {1957},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1957_114_3_a5/}
}