title: Comment on "Casimir energies: temperature dependence, dispersion, and anomalies".
abstract: It is pointed out that the Casimir energy in a medium can be obtained most directly from the zero-point energy of the electromagnetic field because of its reduced propagation velocity. This brings to the fore again the old problem related to how the principle of relativity is combined with the Maxwell field equations in a continuous medium.
authors.forename: Finn
authors.initials: F
authors.lastname: Ravndal