We present the results of analytical evaluation of the indirect RKKY
interaction in a layered metal with nearly nested (almost squared) Fermi
surface. The final expressions are obtained in closed form as a combination of
Bessel functions. We discuss the notion of the
``2k_F'' oscillations and show that they occur as the far asymptote of our
expressions. We show the existence of the intermediate asymptote of the
interaction which is of the sign-reversal antiferromagnetic type and is the
only term surviving in the limit of exact nesting. A good accordance of our
analytical formulas with numerical findings is demonstrated until the
interatomic distances. The obtained expressions for the Green's functions
extend the previous analytical results into the region of intermediate
distances as well.Comment: 9 pages, REVTEX, 3 .eps figures, to appear in PRB 1 Oct 199