\[R_{m,n}(a,b,z)=\begin{cases}O\left(e^{-|z|}z^{-m}\right),&|\operatorname{ph}z|%
\leq\pi,\\
O\left(e^{z}z^{-m}\right),&\pi\leq|\operatorname{ph}z|\leq\tfrac{5}{2}\pi-%
\delta.\\
\end{cases}\]