geometric algebra(英语:geometric algebra), with the planes of rotations associated with simple bivectors(英语:Bivector#Simple bivectors) in the algebra. 本文所有平面都通過原點(即包含零向量。)
finite simple group, J. Algebra 20 (1972) 540-569 and 34 (1975) 188-189. Volker Gebhardt, Two short presentations for Lyons' sporadic simple group, Experimental