In this appendix we give the expression of the unitarity corrections to the form factors F, G, and R ([54],[55],[62]).
with
The loop integrals 
which occur
in these expressions are listed in appendix B. The
functions
and 
depend on the scale 
at which the
loops are renormalized. The scale drops out in the expression
for the full amplitude.
The imaginary part of 
contains
the I = 0, S-wave 
phase shift
as well as contributions from 
and 
intermediate states. The functions 
and 
are
real in the physical region.
with
The imaginary part of 
contains the
I=1, P-wave phase shift
as well as contributions from 
intermediate states.
The function 
is real in the physical region.
The unitarity corrections 
in the form factor R in
(5.58) are
with
cm Acknowledgements
We thank G. Pancheri for the perfect organization of the DA
NE Workshops
and the INFN for the hospitality in Frascati.
We have enjoyed numerous interesting discussions
with the members of the working groups.
We thank J. Beringer for
checking traces in 
, M. Candusso for doing the contour plots
and C. Riggenbach for providing us with numerical routines for 
.
S. Blaser kindly allowed us to include his work [85] on 
decays.
