collision occurs in comparison with $L_v(\omega)$ (see (\[1.2\])). This was pointed out in [@KS3].

In the experiment [@exp1] devoted to study of the bremsstrahlung spectrum $d\sigma_{\gamma}(\omega)$ carried out in the electron-positron colliding beam facility VEPP-4 of Institute of Nuclear Physics at an energy $\varepsilon=1.84~$GeV, a deviation of the bremsstrahlung spectrum from the standard QED spectrum was observed. This was attributed to the smallness of the transverse size of the colliding beams. Theoretically the problem of finite transverse dimensions was investigated in [@BKS1] were the bremsstrahlung spectrum at $e^+e^-$ collision have was calculated to within the power accuracy (the neglected terms are of the order $1/\gamma=m/\varepsilon$) . Later the problem was analyzed in [@BD], [@KPS], [@KSS] where the found bremsstrahlung spectra coincide with obtained in [@BKS1].

It should be noted that in [@BKS1] (as well as in all other papers mentioned above) an incomplete expression for the bremsstrahlung spectrum was calculated. One has to perform the subtraction associated with the extraction of pure fluctuation process. Let us discuss this item in some details. The momentum transfer ${\bf q}$ at collision is important for the radiation process (the cross section contains factor ${\bf q}^2$ at ${\bf
q}^2 \ll m^2$). At the beam 