  In this note, we derive Ewald sums for Yukawa potential for three dimensional
systems with two dimensional periodicity. This sums are derived from the Ewald
sums for Yukawa potentials with three dimensional periodicity [G. Salin and
J.-M. Caillol, J. Chem. Phys. {\bf 113}, 10459 (2000)] by using the method
proposed by Parry for the Coulomb interactions [D.E. Parry, Surf. Sci. {\bf
49}, 433 (1975); {\bf 54}, 195 (1976)].
