@article{schulten:1975:ere,
    author = {Schulten, Klaus and Gordon, Roy G.},
     title = {Exact recursive evaluation of {$3j$}- and {$6j$}-coefficients
              for quantum-mechanical coupling of angular momenta},
   journal = {J. Mathematical Phys.},
    volume = {16},
      year = {1975},
    number = {10},
     pages = {1961–1970},
   mrclass = {81.65},
  mrnumber = {MR0381597 (52 \#2490)},
mrreviewer = {J.-L. Calais},
       doi = {10.1063/1.522426}}