RDP 8707: Asymmetric Information and Bid-Ask Spreads in the Eurocurrency Markets Equation

\begin{array}{l} σ^{2} = σ_{ε}^{2} + a^{2} σ_{u}^{4} σ_{x}^{2} \\ and R = σ_{ε}^{2} / σ^{2} . \end{array}