@article{teukolsky:1972:rbh,
    author = {Teukolsky, S. A.},
     title = {Rotating black holes: Separable wave equations for
              gravitational and electromagnetic perturbations},
   journal = {Phys. Rev. Lett.},
    volume = {29},
    number = {16},
      year = {1972},
     pages = {1114–1118},
       doi = {10.1103/PhysRevLett.29.1114}}