David Hestenes was Professor of Physics at Arizona State University. This archive preserves his papers about geometric algebra and geometric calculus, electron theory, and modeling theory for science education.
Geometric Calculus Research & Development (archive of geocalc.clas.asu.edu)
Papers on physics and mathematics
Papers on modeling and education
Personal retrospectives include an interview from 2012 and The Genesis of Geometric Algebra from 2016.