Clifford Algebra a Visual Introduction by Steven Lahar
This is a good introduction to CliffordAlgebra and its history which is now extended as a series.
- http://slehar.wordpress.com/2014/03/18/clifford-algebra-a-visual-introduction/
- http://slehar.wordpress.com/2014/06/26/geometric-algebra-projective-geometry/
- http://slehar.wordpress.com/2014/07/24/geometric-algebra-conformal-geometry/
See also CliffordAlgebraResources