@article{10_4064_sm_75_1_37_49,
     author = {Zbigniew S{\l}odkowski},
     title = {A criterion for subharmonicity of a function of the spectrum},
     journal = {Studia Mathematica},
     pages = {37--49},
     publisher = {mathdoc},
     volume = {75},
     number = {1},
     year = {1982},
     doi = {10.4064/sm-75-1-37-49},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm-75-1-37-49/}
}