Müller, Eberhard E. (1986) Bose-Einstein Condensation in Dependence of the Mean Energy Density. (Preprint)
Müller, Eberhard E. (1985) Bose-Einstein Condensation of Free Photons. (Preprint)
Müller, Eberhard E. (1985) Scalar Potentials for Vector Fields and an Application to Quantum Electrodynamics. (Preprint)