Our next goal is to discuss the concept of periodization, i.e., the Poisson summation formula for two-dimensional regular regions, i.e., planar “potato slices” (cf. Figure 13.1). An essential tool is the two-dimensional Fourier inversion formula (as proposed by W. Freeden [1978a]). More concretely, Section 13.1 provides a particular treatment of the pointwise Fourier inversion formula within a (meta)harmonically oriented framework involving Bessel functions.