\[{{}_{2}\phi_{1}}\left({q^{-n},b\atop c};q,z\right)=\frac{\left(c/b;q\right)_{n%
}}{\left(c;q\right)_{n}}b^{n}{{}_{3}\phi_{1}}\left({q^{-n},b,q/z\atop bq^{1-n}%
/c};q,z/c\right),\]