@article{ZNSL_1991_192_a1,
     author = {D. Yu. Grigor'ev},
     title = {Complexity of solving linears systems in the rings of differential operators},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {47--60},
     publisher = {mathdoc},
     volume = {192},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1991_192_a1/}
}