@article{DE_1995_31_11_a13,
     author = {M. M. Khapaev},
     title = {Differential equations that contain singular manifolds in control and minimization problems},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1886--1892},
     publisher = {mathdoc},
     volume = {31},
     number = {11},
     year = {1995},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1995_31_11_a13/}
}