@article{FPM_2008_14_4_a10,
     author = {A. B. Levin},
     title = {Dimension polynomials of intermediate differential fields and the strength of a~system of differential equations with group action},
     journal = {Fundamentalʹna\^a i prikladna\^a matematika},
     pages = {167--180},
     publisher = {mathdoc},
     volume = {14},
     number = {4},
     year = {2008},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FPM_2008_14_4_a10/}
}