@article{ISU_2011_11_2_a9,
     author = {V. A. Kovalev and Yu. N. Radayev},
     title = {An optimal system constructing algorithm for symmetry algebra of three-dimensional equations of the perfect plasticity},
     journal = {Izvestiya of Saratov University. Mathematics. Mechanics. Informatics},
     pages = {61--77},
     publisher = {mathdoc},
     volume = {11},
     number = {2},
     year = {2011},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ISU_2011_11_2_a9/}
}