\[Y_{\nu}'\left(\nu z\right)\sim\frac{2}{z}\left(\frac{1-z^{2}}{4\zeta}\right)^{%
\frac{1}{4}}\*\left(\frac{\operatorname{Bi}\left(\nu^{\frac{2}{3}}\zeta\right)%
}{\nu^{\frac{4}{3}}}\sum_{k=0}^{\infty}\frac{C_{k}(\zeta)}{\nu^{2k}}+\frac{%
\operatorname{Bi}'\left(\nu^{\frac{2}{3}}\zeta\right)}{\nu^{\frac{2}{3}}}\sum_%
{k=0}^{\infty}\frac{D_{k}(\zeta)}{\nu^{2k}}\right),\]