M. Frechet, Sur quelques points du calcul fonctionnel, Rend. Circ. Mat.
Palermo, 22 (1906), 1-74.
P. R. Halmos, Introduction to Hilbert Space and the Theory of Spectral
Multiplicity, Chelsea, New York, 1951.
F. Hausdorff, Grundzuege der Mengenlehre, Leipzig, 1914.
E. W. Hobson, The Theory of Functions of a Real Variable and the Theory
of Fourier's Series, Vol. 1, 3rd ed., Cambridge University Press, Cambridge,
1927..
P. Jordan and J. von Newmann, On inner products in linear metric spaces,
Ann. of Math., 36 (1935), 719-723.
A. N. Kolmogorov, Zur Normierbarkeit eines allgemeinen topologischen
linearen Raumes, Studia Math., 5 (1934), 29-33.
A. N. Kolmogorov and S. V. Fomin, Elements of the Theory of Functions
and Functional Analysis, Vol. 1. Metric and Normed Spaces, Graylock Press,
Rochester, N. Y., 1957.
Liusternik and V. Sobolev, Elements of Functional Analysis, Frederick
Ungar, New York, 1961.
Ch. Meray, Nouveau Precis d'Analyse Infinitesimale, Paris, 1872.
J. von Newmann, Allgemeine Eigenwerttheorie Hermitischer Funktionaloper-
atoren, Math. Ann., 102 (1929), 49-131.
M. H. Stone, The theory of representation for Boolean algebras, Trans. Amer.
Math. Soc., 40 (1936), 37-111.
M. H. Stone, Linear Transformations in Hilbert Space, Colloquium Publica-
tion 15, American Mathematical Society, New York, 1932.
A. E. Taylor, Introduction to Functional Analysis, Wiley, New York, 1958.
