@article{INTG_1985_17_a1,
     author = {Yu. I. Ermakov},
     title = {On the theory of invariants of structural tensor fields},
     journal = {Itogi Nauki i Tekhniki. Seriya Problemy Geometrii. Trudy Geometricheskogo Seminara},
     pages = {51--86},
     year = {1985},
     volume = {17},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/INTG_1985_17_a1/}
}