@article{DAN_1983_271_5_a11,
     author = {M. M. Khapaev},
     title = {A. {N.~Tikhonov's} theorem for singularly perturbed systems},
     journal = {Doklady Akademii Nauk},
     pages = {1074--1077},
     year = {1983},
     volume = {271},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1983_271_5_a11/}
}