  All existing derivations of the electrostatic potential of a uniformly
charged disk are technically rather involved. In an old and now almost
forgotten publication, Duffin and McWhirter proposed a method for calculating
the electrostatic potentials of planar bodies by a skillful application of
Green's theorem. It is shown that this method significantly simplifies the
problem of calculating the electrostatic potential of a uniformly charged disk
and makes it an almost trivial task.
