- An Introduction to the Lorentz-Dirac Equation - Notes by Eric Poisson providing two derivations of the Lorentz--Dirac equation.
- Publications in Physics and Mathematics by Walter Pfeifer - A textbook for relativistic quantum mechanics with detailed description of the Dirac equation and other publications.
- Relativistic Quantum Mechanics - An electronic textbook by Walter Pfeifer that can be ordered free.