@article{10_4064_sm_122_1_39_54,
     author = {Peter Vieten},
     title = {Four characterizations of scalar-type operators with spectrum in a half-line},
     journal = {Studia Mathematica},
     pages = {39--54},
     publisher = {mathdoc},
     volume = {122},
     number = {1},
     year = {1997},
     doi = {10.4064/sm-122-1-39-54},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm-122-1-39-54/}
}