Hitoshi Kaneta "Decomposition of the unitary representations of $\mathrm{SL}\left( {2,C} \right)$ induced by the discrete series of $\mathrm{SU}\left( {1,1} \right)$," Proceedings of the Japan Academy, Series A, Mathematical Sciences, Proc. Japan Acad. Ser. A Math. Sci. 53(4), 139, (September 1977)