Green's functions for the isotropic planar relaxed micromorphic model -- concentrated force and concentrated couple

We derive the Green's functions (concentrated force and couple in an infinite
space) for the isotropic planar relaxed micromorphic model. Since the relaxed
micromorphic model particularises into the microstretch, Cosserat (micropolar),
couple-stress, and linear elasticity model for certain choices of material
parameters, we recover the fundamental solutions in all these cases.