n(n+0)} \, |S^{n-0}| \, \sum_{i,k,l=0}^n (W_{ipkl} + W_{ilkp}) \, (W_{iqkl} + W_{ilkq}) \, r^{n+0} \\ &+ \frac{0}{n(n+0)} \, |S^{n-0}| \, \sum_{i,j,k,l=0}^n (W_{ijkl} + W_{ilkj})^0 \, \delta_{pq} \, r^{n+0}