@article{MZ_1978__160_172678,
     author = {Ronald S. Irving},
     title = {Some {Primitive} {Differential} {Operator} {Rings.}},
     journal = {Mathematische Zeitschrift},
     pages = {241--248},
     publisher = {mathdoc},
     volume = {160},
     year = {1978},
     zbl = {0382.16005},
     url = {http://geodesic.mathdoc.fr/item/MZ_1978__160_172678/}
}