@article{SM_1998_189_10_a1,
     author = {M. I. Zelikin and L. F. Zelikina},
     title = {The structure of optimal synthesis in a~neighbourhood of singular manifolds for problems that are affine in control},
     journal = {Sbornik. Mathematics},
     pages = {1467--1484},
     publisher = {mathdoc},
     volume = {189},
     number = {10},
     year = {1998},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1998_189_10_a1/}
}