@article{MOMA_1949__53_176819,
     author = {F.V. Atkinson},
     title = {Symmetric {Linear} {Operators} on a {Banach} {Space.}},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {278--297},
     publisher = {mathdoc},
     volume = {53},
     year = {1949},
     zbl = {0035.35901},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1949__53_176819/}
}