Möller, Tilman, and Gerhard Röhrle. “Nice Restrictions of Reflection Arrangements”. The Electronic Journal of Combinatorics 24, no. 3 (September 8, 2017): #P3.44. Accessed April 18, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v24i3p44.