\[\lim_{\mu\to 0,\;\ifrac{\lambda}{\mu}\to 0}r_{n}\left(\ifrac{x}{(2\lambda\mu)}%
;\ifrac{\lambda}{\mu},\ifrac{qa\mu}{\lambda},\ifrac{1}{(\lambda\mu)},qb\lambda%
\mu\,|\,q\right)=p_{n}\left(x;a,b;q\right).\]