@article{SM_2007_198_10_a4,
     author = {S. E. Pastukhova},
     title = {Degenerate equations of monotone type: {Lavrent'ev} phenomenon and attainability problems},
     journal = {Sbornik. Mathematics},
     pages = {1465--1494},
     year = {2007},
     volume = {198},
     number = {10},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2007_198_10_a4/}
}