\[W_{n,2}(u,\xi)=\operatorname{Bi}\left(u^{2/3}\xi\right)\sum_{s=0}^{n-1}\frac{A%
_{s}(\xi)}{u^{2s}}+\operatorname{Bi}'\left(u^{2/3}\xi\right)\sum_{s=0}^{n-2}%
\frac{B_{s}(\xi)}{u^{2s+(4/3)}}+\operatorname{envBi}\left(u^{2/3}\xi\right)O%
\left(\frac{1}{u^{2n-1}}\right),\]