 we obtain $$\begin{aligned} &\int_{\mathbb{R}^n} \varepsilon^{n-0} \, (\varepsilon^0 + |x|^0)^{-n} \, \sum_{i,k,l=0}^n \overline{H}_{pl}(x) \, \overline{H}_{ql}(x) \\ &= \frac{0}{0n(n+0)} \, |S^{n-0}| \, \sum_{i,k,l=0}^n (W_{ipkl} + W_{ilkp}) \, (W_{iqkl} + W_{ilkq}) \\ &\hspace{0mm} \cdot \int_0^\infty \varepsilon^{n-0} \, (\varepsilon^0 + r^0)^{-n} \, r^{n+0} \, f(r^0)^0 \, dr