On Hille's spectral theory and operational calculus for semi-groups of operators in Hilbert space
Compositio Mathematica, Volume 14 (1959-1960), p. 71-73
@article{CM_1959-1960__14__71_0,
     author = {Foia\c s, Ciprian},
     title = {On Hille's spectral theory and operational calculus for semi-groups of operators in Hilbert space},
     journal = {Compositio Mathematica},
     publisher = {Kraus Reprint},
     volume = {14},
     year = {1959-1960},
     pages = {71-73},
     zbl = {0086.31903},
     mrnumber = {105027},
     language = {en},
     url = {http://www.numdam.org/item/CM_1959-1960__14__71_0}
}
Foiaş, Ciprian. On Hille's spectral theory and operational calculus for semi-groups of operators in Hilbert space. Compositio Mathematica, Volume 14 (1959-1960) pp. 71-73. http://www.numdam.org/item/CM_1959-1960__14__71_0/

E. Hille [1] Functional Analysis and Semi-groups. New York, 1948. | MR 25077 | Zbl 0033.06501

C. Foiaş [2] La mesure harmonique spectrale et la théorie spectrale des opérateurs généraux d'un espace de Hilbert. Bull. de la Soc. Math. de France 85, (1957). | Numdam | MR 100790 | Zbl 0084.10903

J.V. Neumann [3] Eine Spektraltheorie für allgemeine Operatoren eines unitären Raumes, Math. Nachr. 4, (1951). | MR 43386 | Zbl 0042.12301

F. Riesz and B. Sz.-Nagy [4] Leçons d'analyse fonctionnelle, Budapest, 1953. | Zbl 0051.08403