1. Anusiak, Z.: Symmetry of
$$L_1$$
L
1
-group algebra of locally compact groups with relatively compact classes of conjugated elements. Bull. Acad. Polon. Sci. Sér. Sci. Ser. Math. Astronom. Phys. 18, 329–332 (1970)
2. O. Bratelli and D. W. Robinson, Operator Algebras and Quantum Statistical Mechanics, I, Springer-Verlag (New York–Heidelberg, 2002)
3. F. F. Bonsall and J. Duncan, Complete Normed Algebras, Springer-Verlag (Berlin, 1973)
4. J. Dixmier,
$$C^{*} $$
C
∗
-algebras, translated from the French by F. Jellett, North-Holland Mathematical Library, Vol. 15, North-Holland Publishing Co. (Amsterdam–New York–Oxford, 1977)
5. Doran, R.S., Tiller, W.: Extensions of pure positive functionals on Banach
$$^{*} $$
∗
-algebras. Proc. Amer. Math. Soc. 82, 583–586 (1981)