@article{DAN_1963_152_3_a8,
     author = {M. A. Krasnosel'skii and V. V. Strygin},
     title = {Calculation of the rotation of completely continuous vector fields associated with the problem of periodic 
},
     journal = {Doklady Akademii Nauk},
     pages = {540--543},
     publisher = {mathdoc},
     volume = {152},
     number = {3},
     year = {1963},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1963_152_3_a8/}
}