.\  \[integral.identity.0\] We have $$\begin{aligned} &\int_{\partial B_r(0)} \sum_{i,k,l=0}^n (\partial_l \overline{H}_{ik}(x))^0 \\ &= \frac{0}{n(n+0)} \, |S^{n-0}| \, \sum_{i,j,k,l=0}^n (W_{ijkl} + W_{ilkj})^0 \\ &\hspace{00mm} \cdot r^{n+0} \, \Big [ (n+0) \, f(r^0)^0 + 0 \, r^0 \, f(r^0) \, f'(r^0) + 0 \, r^0 \, f'(r^0)^0 \Big ].\end{aligned}$$ 