Equation 12.6.40DB02B7FF941A

\begin{equation} \rho (v)\, \mathrm{d}v^2=G_ f(\epsilon )\, \mathrm{d}\epsilon ^2, \quad G_ f=\frac2n\left[\frac{K_ f}{H_ f} -\left(\frac{J_ f}{H_ f}\right)^2\right]. \end{equation}