@article{10_1017_S0017089507003370,
     author = {COUTINHO, S. C.},
     title = {NONHOLONOMIC {SIMPLE} {D-MODULES} {FROM} {SIMPLE} {DERIVATIONS}},
     journal = {Glasgow mathematical journal},
     pages = {11--21},
     year = {2007},
     volume = {49},
     number = {1},
     doi = {10.1017/S0017089507003370},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089507003370/}
}