Fima, P., and L. I. Vainerman. “A Locally Compact Quantum Group of Triangular Matrices”.
Ukrains’kyi Matematychnyi Zhurnal
, vol. 60, no. 4, Apr. 2008, pp. 564–576,
https://umj.imath.kiev.ua/index.php/umj/article/view/3176
.