@article{FPM_2004_10_1_a3,
     author = {D. K. Demskoi and S. Ya. Startsev},
     title = {On construction of symmetries from integrals of hyperbolic partial differential systems},
     journal = {Fundamentalʹna\^a i prikladna\^a matematika},
     pages = {29--37},
     publisher = {mathdoc},
     volume = {10},
     number = {1},
     year = {2004},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FPM_2004_10_1_a3/}
}