@article{FAA_1978_12_1_a0,
     author = {V. I. Arnol'd},
     title = {Index of a singular point of a vector field, the {Petrovskii--Oleinik} inequality, and mixed hodge structures},
     journal = {Funkcionalʹnyj analiz i ego prilo\v{z}eni\^a},
     pages = {1--14},
     publisher = {mathdoc},
     volume = {12},
     number = {1},
     year = {1978},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FAA_1978_12_1_a0/}
}