'T. Kato: Semi-groups and temporally inhomogeneous evolution equations.- J.L. Lions: Equations
différentielles opérationnelles dans les espaces de Hilbert.- L. Nirenberg: Equazioni
differenziali ordinarie negli spazi di Banach.- R.S. Phillips: Semi-groups of contraction
operators.- L. Amerio: Almost-periodic equations in Hilbert spaces.- G.C. Rota: A limit theorem
for the time-dependent evolution equation.- S. Zaidman: Existence and almost periodicity for
some differential euqations in Hilbert spaces.