@article{TM_2014_285_a15,
     author = {A. N. Pechen and N. B. Il'in},
     title = {Coherent control of a~qubit is trap-free},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {244--252},
     publisher = {mathdoc},
     volume = {285},
     year = {2014},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TM_2014_285_a15/}
}