@article{VMUMM_2023_4_a8,
     author = {F. M. Malyshev},
     title = {Invariant sums of products of differentials},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {53--57},
     year = {2023},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_2023_4_a8/}
}