1. T.A. Bouma, From Unoriented Subspaces to Blade Operators, Chapter 4 in this volume.
2. L. Dorst, Honing geometric algebra for its use in the computer sciences. In Geometric Computing with Clifford Algebra (G. Sommer, ed.), Springer, 2001. Preprint available at http://www.science.uva.nl/~leo/clifford/
3. L.Dorst, S.Mann, T.A.Bouma, GABLE: A Geometric AlgeBra Learning Environment, www. science.uva.nl/~leo/clifford/gable.html
4. D. Hestenes and G Sobczyk, Clifford Algebra to Geometric Calculus, D. Reidel, Dordrecht, 1984.
5. P. Lounesto, Marcel Riesz’s work on Clifford algebras. In Clifford Numbers and Spinors (E.F. Bolinder and P. Lounesto, eds.), Kluwer Academic Publishers, pp. 215–241, 1993.