@article{DAN_1961_138_2_a1,
     author = {L. N. Gagen-Torn and S. G. Mikhlin},
     title = {On the solvability of non-linear {Ritz} systems},
     journal = {Doklady Akademii Nauk},
     pages = {258--260},
     publisher = {mathdoc},
     volume = {138},
     number = {2},
     year = {1961},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1961_138_2_a1/}
}