@article{SM_1978_34_6_a0,
     author = {N. V. Grigorenko},
     title = {On {Picard{\textendash}Vessiot} extensions of differential fields},
     journal = {Sbornik. Mathematics},
     pages = {701--706},
     year = {1978},
     volume = {34},
     number = {6},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1978_34_6_a0/}
}