@article{berry:1966:uap,
    author = {Berry, M. V.},
     title = {Uniform approximation for potential scattering involving a
              rainbow},
   journal = {Proc. Phys. Soc.},
    volume = {89},
      year = {1966},
    number = {3},
     pages = {479–490},
       doi = {10.1088/0370-1328/89/3/301},
     zblno = {0139.42001}}