@book{appel:1968:ntac,
    author = {Appel, H.},
     title = {Numerical Tables for Angular Correlation Computations in
              $\alpha$-, $\beta$- and $\gamma$-Spectroscopy: $3j$-, $6j$-, $9j$-Symbols,
              F- and $\Gamma$-Coefficients},
    series = {Landolt-B\"{o}rnstein Numerical Data and Functional Relationships
              in Science and Technology},
 publisher = {Springer-Verlag},
      year = {1968},
      isbn = {978-3-540-04218-1}}