  A general technique to analyze the classical interaction between ideal
topological insulators, and electromagnetic sources and fields, has been
previously elaborated. Nevertheless it is not immediately applicable in the
laboratory as it fails to describe real ponderable media. In this work we
provide a description of real topologically insulating materials taking into
account their dielectric and magnetic properties. For inhomogeneous
permittivity and permeability, the problem of finding the Green's function must
be solved in an ad hoc manner. Nevertheless, the physically feasible cases of
piecewise constant $\varepsilon, \mu$ and $\theta$ make the problem tractable,
where $\theta$ encodes the topological magnetoelectric polarizability
properties of the medium. To this end we employ the Green's function method to
find the fields resulting form the interaction between these materials and
electromagnetic sources. Furthermore we exploit the fact that in the cases here
studied, the full Green's function can be successfully found if the Green's
function of the corresponding ponderable media with $\theta = 0$ is known. Our
results, satisfactorily reproduce previously existing ones and also generalize
some others. The method here elaborated can be exploited to determine the
electromagnetic fields for more general configurations aiming to measure the
interaction between real 3D topological insulators and electromagnetic fields.
