@article{DE_2004_40_6_a0,
     author = {E. E. Bukzhalev},
     title = {On the {Construction} of {Upper} and {Lower} {Solutions} by the {Nagumo} {Method}},
     journal = {Differencialʹnye uravneni\^a},
     pages = {723--730},
     publisher = {mathdoc},
     volume = {40},
     number = {6},
     year = {2004},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_2004_40_6_a0/}
}