The codes that will be used are:
- () cross section near resonance region
whitlow (wiser) - () cross section in deep inelastic region ()
rosetail - elastic tail
pos_epc, pos_wiser - cross section
For positron yield only one reaction channel has been included for calculating
. The code pos_epc was first
developed by J.P.Chen based on SLAC data and epc code for yield of .
Code pos_wiser was developed by using the same reaction channel, but using
wiser's fit for yield of .
 J. W. Lightbody, Jr., J. S. O'Connell, Computers in Physics,
 L. W. Whitlow, SLAC-Report-357, (1990);
 D. E. Wiser, Ph.D. thesis, Univ. of Wisconsin, (1977);
 Mo and Tsai,Rev. Mod. Phys., 41, 205 (1969);
 Stein, et. al. Phys. Rev. D,12, 1884 (1975).