@article{LJM_2005_17_a6,
     author = {C. V. Jensen},
     title = {Linear {ODEs} and $\mathcal D$-modules, solving and decomposing equations using symmetry methods},
     journal = {Lobachevskii journal of mathematics},
     pages = {149--212},
     publisher = {mathdoc},
     volume = {17},
     year = {2005},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/LJM_2005_17_a6/}
}