@article{AFM_1972_501-520_a7,
     author = {Ilppo Simo Louhivaara and Christian G. Simader},
     title = {\"Uber nichtelliptische lineare partielle {Differentialoperatoren} mit konstanten {Koeffizienten}},
     journal = {Annales Fennici Mathematici},
     publisher = {mathdoc},
     volume = {501-520},
     year = {1972},
     doi = {10.5186/aasfm.1972.513},
     language = {de},
     url = {http://geodesic.mathdoc.fr/articles/10.5186/aasfm.1972.513/}
}