\begin{array}{rcl} E (- φ, k) & = & - E (φ, k) \\ E (φ + m π, k) & = & E (φ, k) + 2 m E (k); φ \notin [0, \frac{π}{2}] \\ E (φ, k) & = & \sin φ R_{F} (\cos^{2} φ, 1 - k^{2} \sin^{2} φ, 1) - \frac{1}{3} k^{2} \sin^{3} φ R_{D} (\cos^{2} φ, 1 - k^{2} \sin^{2} φ, 1) \end{array}