@article{MS2_1964__15_165884,
     author = {Konrad J\"orgens},
     title = {Wesentliche {Selbstadjungiertheit} singul\"arer elliptischer {Differentialoperatoren} zweiter {Ordnung} in {C...(G).}},
     journal = {Mathematica Scandinavica},
     pages = {5--17},
     publisher = {mathdoc},
     volume = {15},
     year = {1964},
     zbl = {0132.07601},
     url = {http://geodesic.mathdoc.fr/item/MS2_1964__15_165884/}
}