@article{MS2_1972__30_166239,
     author = {Erling Stormer},
     title = {Invariant {States} of von {Neumann} {Algebras.}},
     journal = {Mathematica Scandinavica},
     pages = {253--256},
     publisher = {mathdoc},
     volume = {30},
     year = {1972},
     zbl = {0245.46086},
     url = {http://geodesic.mathdoc.fr/item/MS2_1972__30_166239/}
}