@article{MZM_1990_47_5_a8,
     author = {V. Yu. Ovsienko},
     title = {Classification of third-order linear differential equations and symplectic sheets of the {Gel'fand--Dikii} bracket},
     journal = {Matemati\v{c}eskie zametki},
     pages = {62--70},
     publisher = {mathdoc},
     volume = {47},
     number = {5},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1990_47_5_a8/}
}