Covariance matrix for the differential cross section
$d\sigma(e^+e^- \to \pi^+\pi^-\gamma)/ds_{\pi}$ in the angular region 
$\theta_{\pi\pi}<15^o$ or  $\theta_{\pi\pi}>165^o$, 
$0^o<\theta_{\pi}<180^o$.

The overall matrix is 60x60, in the energy region 0.35<s_pi<0.94, 
as in the table 1, page 16 of the article.

The matrix is cut into 6 slices (60;10) like this
i=1    /1,..,10|11,..,20|21,..,30|31,..,40|41,..,50|51,..,60\
i=2    |....   |.....   |.....   |.....   |.....   |.....   |
       |....   |.....   |.....   |.....   |.....   |.....   |
i=..   |....   |.....   |.....   |.....   |.....   |.....   |
       |....   |.....   |.....   |.....   |.....   |.....   |
i=59   |....   |.....   |.....   |.....   |.....   |.....   |
i=60   \....   |.....   |.....   |.....   |.....   |.....   /

 
Each slice is written in a correspondign file, as in the following:
cov_sppg11.dat  0.35 <ds_{\pi} <0.44 ->1st  slice 
cov_sppg12.dat  0.45 <ds_{\pi} <0.54 ->2nd slice
cov_sppg13.dat  0.55 <ds_{\pi} <0.64
cov_sppg14.dat  0.65 <ds_{\pi} <0.74
cov_sppg15.dat  0.75 <ds_{\pi} <0.84
cov_sppg16.dat  0.85 <ds_{\pi} <0.94 ->6th slice


To store the content in the matrix we suggest the following fortran code:

      real covpi(60,60)
      character*15 xfile
      do i=1,60
        do j=1,60
            covpi(i,j)=0.
         enddo
      enddo


           do i=1,6
 311       FORMAT ('cov_sppg',I2,'.dat')  
           write (xfile,311) 10+i
           open(UNIT=10+i,FILE=xfile,STATUS='OLD')          
           enddo   

           do j=1,60,10
             k1=10+int(j/10)+1
             do i=1,60
                read(k1,303) covpi(i,j),
     $              covpi(i,j+1),covpi(i,j+2),
     $              covpi(i,j+3),covpi(i,j+4),
     $              covpi(i,j+5),covpi(i,j+6),
     $              covpi(i,j+7),covpi(i,j+8),
     $              covpi(i,j+9)
               enddo
         enddo
 303     format(10(1x,f6.3))

               do i=1,6
                  close(10+i)
               enddo
        




  
