As an example in the spherical coordinate system, number RS02 denotes the Green's function for a solid sphere (0 < r < b) with a type 2 (Neumann) boundary condition at r = b. Here letters RS denote the radial-spherical coordinate system, number 0 denotes the zeroth boundary condition (boundedness) at r = 0, and number 2 denotes the type 2 boundary at r = b. The boundary value problem for the RS02 Green's function is given by