1. Bargmann, V.: Irreducible representations of the Lorentz group. Ann. Math.48, 568 (1947).
2. Gel'fand, I. M., andM. A. Neumark: Unitare Darstellungen der Klassischen Gruppen. Berlin: Akademie-Verlag 1957.
3. Hermann, R.: Lie groups for physicists. New York: W. A. Benjamin, Inc. 1965.
4. —— Some properties of representatives of non-compact groups. To appear. Proceedings of the Seminar on Elementary Particles, International Center for Theoretical Physics, Trieste, 1965.
5. —— Group representations and creation operators. Commun. Math. Phys.2, 18–93 (1966).