applies standard asymptotic techniques (Stirling’s approximation, etc) directly to Racah’s sum for the $6j$-symbol; of Ragni (2010) on the computation of $6j$-symbols and on the asymptotics of the $6j$-symbol when some quantum numbers are large and others small; and of Littlejohn and Yu (2009) on uniform approximations for the $6j$-symbol.

In addition there has been some work on the $q$-deformed $6j$-symbol, important for the regularization of the Ponzano-Regge spin-foam model (Turaev and Viro 1992, Ooguri 1992a,b) and for its possible connection to quantum gravity with cosmological constant. In particular, Taylor and Woodward (2004) applied the recursion and WKB method of Schulten and Gordon to the $q$-deformed $6j$-symbol. The results are geometrically interesting (the tetrahedron of Ponzano and Regge is moved from $\Reals^3$ to $S^3$ when the $q$-deformation is turned on), but it seems that at present there is no geometrical treatment of the asymptotics of the $q$-deformed $6j$-symbol, analogous to what is available for the ordinary $6j$-symbol. There is also the recent work of Van der Veen (2010) on the asymptotics of general $q$-deformed spin networks, which treats the problem from the standpoint of knot theory and representation theory. Among other things, this work creates a broad generalization of the 