@article{MZ_1986__191_173686,
     author = {Friedmar Schulz},
     title = {\"Uber nichtlineare, konkave, elliptische {Differentialgleichungen.}},
     journal = {Mathematische Zeitschrift},
     pages = {429--448},
     publisher = {mathdoc},
     volume = {191},
     year = {1986},
     zbl = {0594.35033},
     url = {http://geodesic.mathdoc.fr/item/MZ_1986__191_173686/}
}