  The angular bispectrum of spherical random fields has recently gained an
enormous importance, especially in connection with statistical inference on
cosmological data. In this paper, we provide expressions for its moments of
arbitrary order and we use these results to establish a multivariate central
limit theorem and higher order approximations. The results rely upon
combinatorial methods from graph theory and a detailed investigation for the
asymptotic behaviour of Clebsch-Gordan coefficients; the latter are widely used
in representation theory and quantum theory of angular momentum.
