@article{701830,
     title = {Decomposable systems of differential operators and generalized inverses},
     booktitle = {Proceedings of the 12th Winter School on Abstract Analysis},
     series = {GDML\_Books},
     publisher = {Circolo Matematico di Palermo},
     address = {Palermo},
     year = {1984},
     pages = {83-91},
     mrnumber = {MR0782707},
     zbl = {0569.47042},
     url = {http://dml.mathdoc.fr/item/701830}
}

Delanghe, R. Decomposable systems of differential operators and generalized inverses, dans Proceedings of the 12th Winter School on Abstract Analysis, GDML_Books,  (1984), pp. 83-91. http://gdmltest.u-ga.fr/item/701830/