@article{MAN_1958__135_160602,
     author = {E. Heinz},
     title = {Halbbeschr\"anktheit gew\"ohnlicher {Differentialoperatoren} h\"oherer {Ordnung.}  {Vorwort} von {B.} {L.} {VAN} {DER} {WAEBDEN}},
     journal = {Mathematische Annalen},
     pages = {1--49},
     publisher = {mathdoc},
     volume = {135},
     year = {1958},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/MAN_1958__135_160602/}
}