@article{PORMA_1991__48_4_115763,
     author = {Freire, Nuno C.},
     title = {On the exponential of a bounded linear operator in a {L(E,E)} algebra},
     journal = {Portugaliae mathematica},
     pages = {363--382},
     publisher = {mathdoc},
     volume = {48},
     number = {4},
     year = {1991},
     mrnumber = {1147604},
     zbl = {0776.46008},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1991__48_4_115763/}
}