Kalyuzhnyi, A. A., G. B. Podkolzin, and Yu. Chapovsky. 2007. “Finding Cocycles in the Bicrossed Product Construction for Lie Groups”. Ukrains’kyi Matematychnyi Zhurnal 59 (11): 1510–1522. https://umj.imath.kiev.ua/index.php/umj/article/view/3407.