\[w=\int_{z}^{\infty}\frac{\,\mathrm{d}u}{\sqrt{4u^{3}-g_{2}u-g_{3}}}=\frac{1}{2%
}\int_{z}^{\infty}\frac{\,\mathrm{d}u}{\sqrt{(u-e_{1})(u-e_{2})(u-e_{3})}},\]