  We provide an elementary derivation of the Green's function for Poisson's
equation with Neumann boundary data on balls of arbitrary dimension, which was
recently found in [Sadybekov et al., Eurasian Math. J. 7(2):100-105, 2016]. The
underlying idea consists of first computing the Green's function for the
electroencephalography (EEG) equation (Poisson's equation with dipole
right-hand side) and then deriving the Green's function for Poisson's equation
from that.
