@article{MZ_1976__150_172423,
     author = {Herbert Amann},
     title = {Existence and {Multiplicity} {Theorems} for {Semi-linear} {Elliptic} {Boundary} {Value} {Problems.}},
     journal = {Mathematische Zeitschrift},
     pages = {281--295},
     publisher = {mathdoc},
     volume = {150},
     year = {1976},
     zbl = {0331.35026},
     url = {http://geodesic.mathdoc.fr/item/MZ_1976__150_172423/}
}