@article{RM_1988_43_2_a21,
     author = {M. I. Zelikin},
     title = {Group symmetry in degenerate extremal problems},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {189--190},
     publisher = {mathdoc},
     volume = {43},
     number = {2},
     year = {1988},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1988_43_2_a21/}
}