@article{10_4064_ap_16_3_353_357,
     author = {M. Altman},
     title = {The cosine equation method for the eigenproblem of bounded normal operators in {Hilbert} space},
     journal = {Annales Polonici Mathematici},
     pages = {353--357},
     publisher = {mathdoc},
     volume = {16},
     number = {3},
     year = {1964},
     doi = {10.4064/ap-16-3-353-357},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/ap-16-3-353-357/}
}