@article{MOMA_1981__91_178029,
     author = {Hermann Sohr},
     title = {Ein neues {Surjektivit\"atskriterium} im {Hilbertraum.}},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {313--338},
     publisher = {mathdoc},
     volume = {91},
     year = {1981},
     zbl = {0452.47014},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1981__91_178029/}
}