Remember: \( \langle\rm{left-out, right-out}\vert V\vert \rm{left-in, right-in}\rangle \).
\( \langle ab\vert V\vert cd\rangle + \langle ij\vert V\vert kl\rangle + \langle ia\vert V\vert bj\rangle \) \( \langle ai\vert V\vert bc\rangle + \langle ij\vert V\vert ka\rangle + \langle ab\vert V\vert ci\rangle \) \( \langle ia\vert V\vert jk\rangle + \langle ab\vert V\vert ij\rangle + \langle ij\vert V\vert ab\rangle \)