Havlíček, M., et al. “Representations of the $q$-Deformed Algebra U$_q$(so$_4$) for $q$ a Root of Unity”. Methods of Functional Analysis and Topology, vol. 4, no. 3, Sept. 1998, pp. 39-44, https://zen.imath.kiev.ua/index.php/mfat/article/view/66.