KalyuzhnyiA. A., PodkolzinG. B., and ChapovskyYu. 2005. “Conditional Expectations on Compact Quantum Groups and Quantum Double Cosets”. Ukrains’kyi Matematychnyi Zhurnal 57 (5), 644–653. https://umj.imath.kiev.ua/index.php/umj/article/view/3630.