References
[1] D. Hestenes and G. Sobczyk, Clifford Algebra to Geometric Calculus , Reidel, 1984.
[2] C. Doran, D. Hestenes, F. Sommen and N. Van Acker, Lie Groups as Spin Groups, J. Math. Phys. 34(8) 3642-3669, 1993.