@article{10_4064_sm_88_3_263_268,
     author = {E. Nordgren and M. Radjabalipour and H. Radjavi and P. Rosenthal},
     title = {Quadratic operators and invariant subspaces},
     journal = {Studia Mathematica},
     pages = {263--268},
     publisher = {mathdoc},
     volume = {88},
     number = {3},
     year = {1988},
     doi = {10.4064/sm-88-3-263-268},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm-88-3-263-268/}
}